Now I have an problem. I can't deny group administration delete own content. I have an group with role admin. Role admin granted to create and adit own content but not delete. In case my admin is not OG admin he can create and edit own content, but not delete. In case I do him OG admin he get ability to delete own content. I think Standard (group post (typically only author may edit).) overwrites restriction to delete own content.

I need to give ability to add/remove users from group and restrict to delete created content. Can You help with this