Query / endpoint to retrieve sponsoring organisations

[afandian]

We need a method for getting a list of Crossref Member IDs for all Sponsoring Organizations (so this is the CS assigned number that we use for Prep for example). Is there another way to get this info other than single api queries for each account name one at a time? Do we have a list of account names and member IDs somewhere that I could do a lookup on or somesuch?

[ynnig]

I'm not sure Amanda meant Sponsoring Organizations - they have no member ID as they are not members, have no content, and would not be represented in the REST API (right now). I think this request is about getting generally any/all member IDs irrespective of the relationship type.