diff --git a/resources/autoload.php b/resources/autoload.php
index 158db4bc..0531a750 100644
--- a/resources/autoload.php
+++ b/resources/autoload.php
@@ -14,6 +14,7 @@
 // load libs
 require_once __DIR__ . "/lib/UnityLDAP.php";
 require_once __DIR__ . "/lib/UnityUser.php";
+require_once __DIR__ . "/lib/PosixGroup.php";
 require_once __DIR__ . "/lib/UnityGroup.php";
 require_once __DIR__ . "/lib/UnityOrg.php";
 require_once __DIR__ . "/lib/UnitySQL.php";
diff --git a/resources/lib/PosixGroup.php b/resources/lib/PosixGroup.php
new file mode 100644
index 00000000..5850e326
--- /dev/null
+++ b/resources/lib/PosixGroup.php
@@ -0,0 +1,82 @@
+<?php
+
+namespace UnityWebPortal\lib;
+
+use PHPOpenLDAPer\LDAPEntry;
+use \Exception;
+
+/*
+does not extend LDAPEntry because UnityGroup extends this and I don't want UnityGroup
+to extend LDAPEntry because the functions from LDAPEntry should not be exposed there
+*/
+class PosixGroup
+{
+    protected LDAPEntry $entry;
+
+    public function __construct(LDAPEntry $entry)
+    {
+        $this->entry = $entry;
+    }
+
+    public function getDN(): string
+    {
+        return $this->entry->getDN();
+    }
+
+    public function equals(PosixGroup $other_group): bool
+    {
+        if (!is_a($other_group, self::class)) {
+            throw new Exception(
+                "Unable to check equality because the parameter is not a " .
+                    self::class .
+                    " object",
+            );
+        }
+        return $this->getDN() == $other_group->getDN();
+    }
+
+    public function exists(): bool
+    {
+        return $this->entry->exists();
+    }
+
+    public function getMemberUIDs(): array
+    {
+        $members = $this->entry->getAttribute("memberuid");
+        sort($members);
+        return $members;
+    }
+
+    public function addMemberUID(string $uid): void
+    {
+        $this->entry->appendAttribute("memberuid", $uid);
+        $this->entry->write();
+    }
+
+    public function addMemberUIDs(array $uids): void
+    {
+        foreach ($uids as $uid) {
+            $this->entry->appendAttribute("memberuid", $uid);
+        }
+        $this->entry->write();
+    }
+
+    public function removeMemberUID(string $uid): void
+    {
+        $this->entry->removeAttributeEntryByValue("memberuid", $uid);
+        $this->entry->write();
+    }
+
+    public function removeMemberUIDs(array $uids): void
+    {
+        foreach ($uids as $uid) {
+            $this->entry->removeAttributeEntryByValue("memberuid", $uid);
+        }
+        $this->entry->write();
+    }
+
+    public function memberUIDExists(string $uid): bool
+    {
+        return in_array($uid, $this->getMemberUIDs());
+    }
+}
diff --git a/resources/lib/UnityGroup.php b/resources/lib/UnityGroup.php
index 688d7106..8d24a61b 100644
--- a/resources/lib/UnityGroup.php
+++ b/resources/lib/UnityGroup.php
@@ -8,12 +8,10 @@
 /**
  * Class that represents a single PI group in the Unity Cluster.
  */
-class UnityGroup
+class UnityGroup extends PosixGroup
 {
     public const string PI_PREFIX = "pi_";
-
     public string $gid;
-    private LDAPEntry $entry;
     private UnityLDAP $LDAP;
     private UnitySQL $SQL;
     private UnityMailer $MAILER;
@@ -26,42 +24,19 @@ public function __construct(
         UnityMailer $MAILER,
         UnityWebhook $WEBHOOK,
     ) {
-        $gid = trim($gid);
+        parent::__construct($LDAP->getPIGroupEntry(trim($gid)));
         $this->gid = $gid;
-        $this->entry = $LDAP->getPIGroupEntry($gid);
-
         $this->LDAP = $LDAP;
         $this->SQL = $SQL;
         $this->MAILER = $MAILER;
         $this->WEBHOOK = $WEBHOOK;
     }
 
-    public function equals(UnityGroup $other_group): bool
-    {
-        if (!is_a($other_group, self::class)) {
-            throw new Exception(
-                "Unable to check equality because the parameter is not a " .
-                    self::class .
-                    " object",
-            );
-        }
-
-        return $this->gid == $other_group->gid;
-    }
-
     public function __toString(): string
     {
         return $this->gid;
     }
 
-    /**
-     * Checks if the current PI is an approved and existent group
-     */
-    public function exists(): bool
-    {
-        return $this->entry->exists();
-    }
-
     public function requestGroup(bool $send_mail_to_admins, bool $send_mail = true): void
     {
         if ($this->exists()) {
@@ -202,7 +177,7 @@ public function approveUser(UnityUser $new_user, bool $send_mail = true): void
     {
         $request = $this->SQL->getRequest($new_user->uid, $this->gid);
         \ensure($new_user->exists());
-        $this->addUserToGroup($new_user);
+        $this->addMemberUID($new_user->uid);
         $this->SQL->removeRequest($new_user->uid, $this->gid);
         if ($send_mail) {
             $this->MAILER->sendMail($new_user->getMail(), "group_user_added", [
@@ -240,14 +215,14 @@ public function denyUser(UnityUser $new_user, bool $send_mail = true): void
 
     public function removeUser(UnityUser $new_user, bool $send_mail = true): void
     {
-        if (!$this->memberExists($new_user)) {
+        if (!$this->memberUIDExists($new_user->uid)) {
             return;
         }
         if ($new_user->uid == $this->getOwner()->uid) {
             throw new Exception("Cannot delete group owner from group. Disband group instead");
         }
         // remove request, this will fail silently if the request doesn't exist
-        $this->removeUserFromGroup($new_user);
+        $this->removeMemberUID($new_user->uid);
         if ($send_mail) {
             $this->MAILER->sendMail($new_user->getMail(), "group_user_removed", [
                 "group" => $this->gid,
@@ -264,7 +239,7 @@ public function removeUser(UnityUser $new_user, bool $send_mail = true): void
 
     public function newUserRequest(UnityUser $new_user, bool $send_mail = true): void
     {
-        if ($this->memberExists($new_user)) {
+        if ($this->memberUIDExists($new_user->uid)) {
             UnityHTTPD::errorLog("warning", "user '$new_user' already in group");
             return;
         }
@@ -310,7 +285,7 @@ public function getRequests(): array
 
     public function getGroupMembers(): array
     {
-        $members = $this->getGroupMemberUIDs();
+        $members = $this->getMemberUIDs();
         $out = [];
         foreach ($members as $member) {
             $user_obj = new UnityUser(
@@ -325,13 +300,6 @@ public function getGroupMembers(): array
         return $out;
     }
 
-    public function getGroupMemberUIDs(): array
-    {
-        $members = $this->entry->getAttribute("memberuid");
-        sort($members);
-        return $members;
-    }
-
     public function requestExists(UnityUser $user): bool
     {
         $requesters = $this->getRequests();
@@ -358,23 +326,6 @@ private function init(): void
         // we need to update the cache here with the memberuid
     }
 
-    private function addUserToGroup(UnityUser $new_user): void
-    {
-        $this->entry->appendAttribute("memberuid", $new_user->uid);
-        $this->entry->write();
-    }
-
-    private function removeUserFromGroup(UnityUser $old_user): void
-    {
-        $this->entry->removeAttributeEntryByValue("memberuid", $old_user->uid);
-        $this->entry->write();
-    }
-
-    public function memberExists(UnityUser $user): bool
-    {
-        return in_array($user->uid, $this->getGroupMemberUIDs());
-    }
-
     private function addRequest(string $uid): void
     {
         $this->SQL->addRequest($uid, $this->gid);
@@ -418,7 +369,7 @@ public static function ownerMail2GID(string $email): string
     public function getGroupMembersAttributes(array $attributes, array $default_values = []): array
     {
         return $this->LDAP->getUsersAttributes(
-            $this->getGroupMemberUIDs(),
+            $this->getMemberUIDs(),
             $attributes,
             $default_values,
         );
diff --git a/resources/lib/UnityOrg.php b/resources/lib/UnityOrg.php
index 07d12ec1..4ccedcc3 100644
--- a/resources/lib/UnityOrg.php
+++ b/resources/lib/UnityOrg.php
@@ -3,10 +3,9 @@
 namespace UnityWebPortal\lib;
 use PHPOpenLDAPer\LDAPEntry;
 
-class UnityOrg
+class UnityOrg extends PosixGroup
 {
     public string $gid;
-    private LDAPEntry $entry;
     private UnityLDAP $LDAP;
     private UnitySQL $SQL;
     private UnityMailer $MAILER;
@@ -19,16 +18,19 @@ public function __construct(
         UnityMailer $MAILER,
         UnityWebhook $WEBHOOK,
     ) {
-        $gid = trim($gid);
+        parent::__construct($LDAP->getOrgGroupEntry(trim($gid)));
         $this->gid = $gid;
-        $this->entry = $LDAP->getOrgGroupEntry($this->gid);
-
         $this->LDAP = $LDAP;
         $this->SQL = $SQL;
         $this->MAILER = $MAILER;
         $this->WEBHOOK = $WEBHOOK;
     }
 
+    public function __toString(): string
+    {
+        return $this->gid;
+    }
+
     public function init(): void
     {
         \ensure(!$this->entry->exists());
@@ -38,19 +40,9 @@ public function init(): void
         $this->entry->write();
     }
 
-    public function exists(): bool
-    {
-        return $this->entry->exists();
-    }
-
-    public function inOrg(UnityUser $user): bool
-    {
-        return in_array($user->uid, $this->getOrgMemberUIDs());
-    }
-
     public function getOrgMembers(): array
     {
-        $members = $this->getOrgMemberUIDs();
+        $members = $this->getMemberUIDs();
         $out = [];
         foreach ($members as $member) {
             $user_obj = new UnityUser(
@@ -64,23 +56,4 @@ public function getOrgMembers(): array
         }
         return $out;
     }
-
-    public function getOrgMemberUIDs(): array
-    {
-        $members = $this->entry->getAttribute("memberuid");
-        sort($members);
-        return $members;
-    }
-
-    public function addUser(UnityUser $user): void
-    {
-        $this->entry->appendAttribute("memberuid", $user->uid);
-        $this->entry->write();
-    }
-
-    public function removeUser(UnityUser $user): void
-    {
-        $this->entry->removeAttributeEntryByValue("memberuid", $user->uid);
-        $this->entry->write();
-    }
 }
diff --git a/resources/lib/UnityUser.php b/resources/lib/UnityUser.php
index 086f53af..16b4514f 100644
--- a/resources/lib/UnityUser.php
+++ b/resources/lib/UnityUser.php
@@ -90,8 +90,8 @@ public function init(
             $org->init();
         }
 
-        if (!$org->inOrg($this)) {
-            $org->addUser($this);
+        if (!$org->memberUIDExists($this->uid)) {
+            $org->addMemberUID($this->uid);
         }
 
         $this->SQL->addLog($this->uid, $_SERVER["REMOTE_ADDR"], "user_added", $this->uid);
@@ -416,6 +416,6 @@ public function isInGroup(string $uid, UnityGroup $group): bool
             $group_checked = $group;
         }
 
-        return in_array($uid, $group_checked->getGroupMemberUIDs());
+        return in_array($uid, $group_checked->getMemberUIDs());
     }
 }
diff --git a/test/functional/AccountDeletionRequestTest.php b/test/functional/AccountDeletionRequestTest.php
index 83177b25..8b595901 100644
--- a/test/functional/AccountDeletionRequestTest.php
+++ b/test/functional/AccountDeletionRequestTest.php
@@ -49,7 +49,7 @@ public function testRequestAccountDeletionUserHasRequest()
         switchUser(...$pi_args);
         $pi = $USER;
         $pi_group = $USER->getPIGroup();
-        $this->assertEqualsCanonicalizing([$pi->uid], $pi_group->getGroupMemberUIDs());
+        $this->assertEqualsCanonicalizing([$pi->uid], $pi_group->getMemberUIDs());
         $user_args = getBlankUser();
         switchUser(...$user_args);
         $this->assertEmpty($USER->getPIGroupGIDs());
diff --git a/test/functional/PIMemberRequestTest.php b/test/functional/PIMemberRequestTest.php
index f42c600a..5d3975f1 100644
--- a/test/functional/PIMemberRequestTest.php
+++ b/test/functional/PIMemberRequestTest.php
@@ -38,7 +38,7 @@ public function testRequestMembership()
         $uid = $USER->uid;
         $this->assertFalse($USER->isPI());
         $this->assertFalse($SQL->requestExists($uid, UnitySQL::REQUEST_BECOME_PI));
-        $this->assertFalse($pi_group->memberExists($USER));
+        $this->assertFalse($pi_group->memberUIDExists($USER->uid));
         try {
             $this->requestMembership($gid);
             $this->assertTrue($SQL->requestExists($uid, $gid));
diff --git a/test/functional/PiMemberApproveTest.php b/test/functional/PiMemberApproveTest.php
index db9cb2b0..51e90acb 100644
--- a/test/functional/PiMemberApproveTest.php
+++ b/test/functional/PiMemberApproveTest.php
@@ -54,7 +54,7 @@ public function testApproveNonexistentRequest()
         $this->assertTrue($piGroup->exists());
         $this->assertGroupMembers($piGroup, [$piUID]);
         $this->assertEmpty($piGroup->getRequests());
-        $this->assertFalse($piGroup->memberExists($user));
+        $this->assertFalse($piGroup->memberUIDExists($user->uid));
         $this->assertEmpty($piGroup->getRequests());
         try {
             $this->expectException(Exception::class); // FIXME more specific exception type
@@ -77,7 +77,7 @@ public function testApproveMemberByPI()
         $this->assertTrue($USER->exists());
         $this->assertTrue($pi_group->exists());
         $this->assertGroupMembers($pi_group, [$pi_uid]);
-        $this->assertTrue(!$pi_group->memberExists($USER));
+        $this->assertTrue(!$pi_group->memberUIDExists($USER->uid));
         $this->assertRequestedMembership(false, $gid);
         try {
             $this->requestGroupMembership($pi_group->gid);
@@ -106,7 +106,7 @@ public function testApproveMemberByPI()
 
             $this->assertTrue(!$pi_group->requestExists($USER));
             $this->assertRequestedMembership(false, $gid);
-            $this->assertTrue($pi_group->memberExists($USER));
+            $this->assertTrue($pi_group->memberUIDExists($USER->uid));
             $this->assertTrue($USER->isQualified());
 
             // $third_request_failed = false;
@@ -137,7 +137,7 @@ public function testApproveMemberByAdmin()
         $this->assertTrue($USER->exists());
         $this->assertTrue($pi_group->exists());
         $this->assertGroupMembers($pi_group, [$pi_uid]);
-        $this->assertTrue(!$pi_group->memberExists($USER));
+        $this->assertTrue(!$pi_group->memberUIDExists($USER->uid));
         $this->assertRequestedMembership(false, $gid);
         try {
             $this->requestGroupMembership($pi_group->gid);
@@ -166,7 +166,7 @@ public function testApproveMemberByAdmin()
 
             $this->assertTrue(!$pi_group->requestExists($USER));
             $this->assertRequestedMembership(false, $gid);
-            $this->assertTrue($pi_group->memberExists($USER));
+            $this->assertTrue($pi_group->memberUIDExists($USER->uid));
             $this->assertTrue($USER->isQualified());
 
             // $third_request_failed = false;
diff --git a/test/functional/PiMemberDenyTest.php b/test/functional/PiMemberDenyTest.php
index f93a1fd5..b7a29c31 100644
--- a/test/functional/PiMemberDenyTest.php
+++ b/test/functional/PiMemberDenyTest.php
@@ -31,17 +31,17 @@ public function testDenyRequest()
         $pi = $USER;
         $piGroup = $USER->getPIGroup();
         $this->assertTrue($piGroup->exists());
-        $this->assertEqualsCanonicalizing([$pi->uid], $piGroup->getGroupMemberUIDs());
+        $this->assertEqualsCanonicalizing([$pi->uid], $piGroup->getMemberUIDs());
         $this->assertEmpty($piGroup->getRequests());
         $requestedUser = new UnityUser(self::$requestUid, $LDAP, $SQL, $MAILER, $WEBHOOK);
         try {
             $piGroup->newUserRequest($requestedUser);
-            $this->assertFalse($piGroup->memberExists($requestedUser));
+            $this->assertFalse($piGroup->memberUIDExists($requestedUser->uid));
 
             $piGroup->denyUser($requestedUser);
             $this->assertEmpty($piGroup->getRequests());
-            $this->assertEqualsCanonicalizing([$pi->uid], $piGroup->getGroupMemberUIDs());
-            $this->assertFalse($piGroup->memberExists($requestedUser));
+            $this->assertEqualsCanonicalizing([$pi->uid], $piGroup->getMemberUIDs());
+            $this->assertFalse($piGroup->memberUIDExists($requestedUser->uid));
         } finally {
             $SQL->removeRequest(self::$requestUid, $piGroup->gid);
         }
diff --git a/test/functional/PiRemoveUserTest.php b/test/functional/PiRemoveUserTest.php
index 7956d1c3..89110da8 100644
--- a/test/functional/PiRemoveUserTest.php
+++ b/test/functional/PiRemoveUserTest.php
@@ -21,7 +21,7 @@ public function testRemoveUser()
         $piUid = $USER->uid;
         $piGroup = $USER->getPIGroup();
         $this->assertTrue($piGroup->exists());
-        $memberUIDs = $piGroup->getGroupMemberUIDs();
+        $memberUIDs = $piGroup->getMemberUIDs();
         // the 0th member of the PI group is the PI
         $this->assertGreaterThan(1, count($memberUIDs));
         // the ordering of the uids in getGroupMemberUIDs is different each time
@@ -37,12 +37,12 @@ public function testRemoveUser()
             }
         }
         $this->assertNotEquals($pi->uid, $memberToDelete->uid);
-        $this->assertTrue($piGroup->memberExists($memberToDelete));
+        $this->assertTrue($piGroup->memberUIDExists($memberToDelete->uid));
         try {
             $this->removeUser($memberToDelete->uid);
-            $this->assertFalse($piGroup->memberExists($memberToDelete));
+            $this->assertFalse($piGroup->memberUIDExists($memberToDelete->uid));
         } finally {
-            if (!$piGroup->memberExists($memberToDelete)) {
+            if (!$piGroup->memberUIDExists($memberToDelete->uid)) {
                 $piGroup->newUserRequest($memberToDelete);
                 $piGroup->approveUser($memberToDelete);
             }
@@ -56,13 +56,13 @@ public function testRemovePIFromTheirOwnGroup()
         $pi = $USER;
         $piGroup = $USER->getPIGroup();
         $this->assertTrue($piGroup->exists());
-        $this->assertTrue($piGroup->memberExists($pi));
+        $this->assertTrue($piGroup->memberUIDExists($pi->uid));
         $this->expectException(Exception::class);
         try {
             $this->removeUser($pi->uid);
-            $this->assertTrue($piGroup->memberExists($pi));
+            $this->assertTrue($piGroup->memberUIDExists($pi->uid));
         } finally {
-            if (!$piGroup->memberExists($pi)) {
+            if (!$piGroup->memberUIDExists($pi->uid)) {
                 $piGroup->newUserRequest($pi);
                 $piGroup->approveUser($pi);
             }
diff --git a/test/phpunit-bootstrap.php b/test/phpunit-bootstrap.php
index c613602f..ce3792ba 100644
--- a/test/phpunit-bootstrap.php
+++ b/test/phpunit-bootstrap.php
@@ -5,6 +5,7 @@
 
 require_once __DIR__ . "/../resources/lib/UnityLDAP.php";
 require_once __DIR__ . "/../resources/lib/UnityUser.php";
+require_once __DIR__ . "/../resources/lib/PosixGroup.php";
 require_once __DIR__ . "/../resources/lib/UnityGroup.php";
 require_once __DIR__ . "/../resources/lib/UnityOrg.php";
 require_once __DIR__ . "/../resources/lib/UnitySQL.php";
@@ -174,9 +175,9 @@ function ensureUserDoesNotExist()
     $SQL->deleteRequestsByUser($USER->uid);
     if ($USER->exists()) {
         $org = $USER->getOrgGroup();
-        if ($org->exists() and $org->inOrg($USER)) {
-            $org->removeUser($USER);
-            ensure(!$org->inOrg($USER));
+        if ($org->exists() and $org->memberUIDExists($USER->uid)) {
+            $org->removeMemberUID($USER->uid);
+            ensure(!$org->memberUIDExists($USER->uid));
         }
         $LDAP->getUserEntry($USER->uid)->delete();
         ensure(!$USER->exists());
@@ -220,9 +221,9 @@ function ensureUserNotRequestedAccountDeletion()
 function ensureUserNotInPIGroup(UnityGroup $pi_group)
 {
     global $USER;
-    if ($pi_group->memberExists($USER)) {
+    if ($pi_group->memberUIDExists($USER->uid)) {
         $pi_group->removeUser($USER);
-        ensure(!$pi_group->memberExists($USER));
+        ensure(!$pi_group->memberUIDExists($USER->uid));
     }
 }
 
@@ -365,7 +366,7 @@ public function assertMessageExists(
     public function assertGroupMembers(UnityGroup $group, array $expected_members)
     {
         sort($expected_members);
-        $found_members = $group->getGroupMemberUIDs();
+        $found_members = $group->getMemberUIDs();
         sort($found_members);
         $this->assertEqualsCanonicalizing($expected_members, $found_members);
     }
diff --git a/webroot/panel/ajax/get_group_members.php b/webroot/panel/ajax/get_group_members.php
index 177d31e0..15c0b08a 100644
--- a/webroot/panel/ajax/get_group_members.php
+++ b/webroot/panel/ajax/get_group_members.php
@@ -8,7 +8,7 @@
 
 $gid = UnityHTTPD::getQueryParameter("gid");
 $group = new UnityGroup($gid, $LDAP, $SQL, $MAILER, $WEBHOOK);
-if (!$group->memberExists($USER)) {
+if (!$group->memberUIDExists($USER->uid)) {
     UnityHTTPD::forbidden("not a group member");
 }
 $members = $group->getGroupMembersAttributes(["gecos", "mail"]);
diff --git a/webroot/panel/groups.php b/webroot/panel/groups.php
index a04030d1..ce76ae12 100644
--- a/webroot/panel/groups.php
+++ b/webroot/panel/groups.php
@@ -39,7 +39,7 @@
                         );
                         UnityHTTPD::redirect();
                     }
-                    if ($pi_account->memberExists($USER)) {
+                    if ($pi_account->memberUIDExists($USER->uid)) {
                         UnityHTTPD::messageError(
                             "Invalid Group Membership Request",
                             "You're already in this PI group"
diff --git a/workers/remove-users-from-group.php b/workers/remove-users-from-group.php
index 20fbb52e..198b9ee9 100755
--- a/workers/remove-users-from-group.php
+++ b/workers/remove-users-from-group.php
@@ -27,7 +27,7 @@ function _die($msg)
 while (($line = fgets($handle)) !== false) {
     $uid = trim($line);
     $user = new UnityUser($uid, $LDAP, $SQL, $MAILER, $WEBHOOK);
-    if (!$group->memberExists($user)) {
+    if (!$group->memberUIDExists($user->uid)) {
         print "Skipping '$uid' who doesn't appear to be in '$gid'\n";
         continue;
     }