I understand the concept of oAuth for signups but in current offerings it seems that I would need to be the one in control of all the keys and setup of such Identity Provider.

Since I host forums for several affiliates as first line of tech support for their services most of their employees monitor the forms and provide assistance. Whenever they have a change in staff I have to add them to their group.

I was wondering if there was a way i could allow the lead person at that company a way to Setup their oAuth for managing their staff and all users who sign up that way are already granted the right permissions.

I am on great terms with my affiliates and could possibly reach out and we could probably get the credentials setup but it would be nice if once I granted a user to manage their users it would be on them to add their oAuth info. Perhaps stored in a hash in the db so I it would be safe. 

Curious if this is something others have done or considered.

There isnt something in which would allow you to change permissions like that at present unfortunately. You would need custom development for this