Reverse entitlement aggregation for Web Services connector

Hi @fernando_delosrios , @Nadim @jrossicare @brian-short ,
I have a similar issue but my API doesn’t have the capability to filter the memberships based on user id.

For example it does not support /Groups/group_id/members?test_user where it should ideally give out the groups present on that particular user. Rather, what it only supports it /Groups/<group id> which would only return the group in their system and their respective group members.

All I have is /Users endpoint which fetches only user attributes and /Groups endpoint which fetches groups in the system and all the members in it.

Is there any way that I can leverage any content from this post and achieve my use case?

Regarding my use-case, I have mentioned detailed information on a separate post below:

Any help is greatly appreciated.
Thanks in advance.

Regards,
Arshad.