I really don't mean to be a jerk, but this sounds like a terrible idea. Four places to send invites from? That's a first world problem, not a startup business opportunity.
Another thing that would be awesome if your could get even finer grained control of some of the services. Like having the ability to maintain some additional Github permissions. A big pain point for us right now is you need to have admin to manage teams, webhooks, etc. Have some levels between admin and write would be great (and I don't blame GH for having these. It's a more enterprise need.)
This seems very valuable to large teams, and like a small convenience to large teams.