That would be very nice if Jive supported that, at least for me as far as the managed rosters go maybe i will look into writing a plugin or something, where you can manage managed rosters externally. I am working on implementing it in my client currently and to say the least its not terribly pretty. The only concern I would have would be setting up the permissions for whom can manage, I would think you might be able to say Components that are directly connected and anyone with jive admin privleges.
As far as handling it on the client side handling it gracefully to me would mean just showing a one time pop up maybe, accept roster additions from this entity.
But thats good though i didn’'t even really think about it in that context.