I just made an Assassins Creed Brotherhood group...!
http://steamcommunity.com/groups/assassinsofthebrotherhood
If you own AC1 or AC2 for PC or if you plan on buying/bought ACB for PC, you're welcome to join.
The only other groups for Assassins Creed Brotherhood were like.. Russian. There was only one other "valid" Assassins Creed Brotherhood group that focused on English ACB. xD