Only optgroup multiple

[ketna11]

Hi, I am using bootstrap-select v1.13.18. I am trying to make , where only optgroup options can be multiple. So if we select non optgroup option, all other options are being deselect (including optgroup options) and if we select optgroup option all non optgroup options are being deseleted, but it is possible to select other optgroup options. Is there any built-in way to do this? <select class="selectpicker" data-container="body" id="levels"> <option value="1">My tasks</option> <optgroup id="departments" label="Departments tasks:" multiple> <option value="11">Service</option> <option value="12">Production</option> </optgroup> <option value="3" selected="">All tasks</option> </select>