I think the "Hero Revolution Universe" is big enough for several groups, though I don't think they each have to interact with each other very much, whether they be Vanguard, EPS, Order, Pantheon, etc.

Chewy's "Fringe Comics" thing is working on something that doesn't have anything to do with Vanguard at all, yet takes place in the same world. I think that's a great idea -- I'm thinking of doing some stories like that myself.