I just cannot wait for this expansion to come out, so I've been scouring the Interwebs to try and find anything about it. I found a good article going into depth about how the multiplayer aspect of the game will work:

www.gametrademagazine.com/Home/1/1/58/818

This article is sweet.

Wont be any 3 way battles, but at least intergration with the previous expansions seems to be superb.