Post your Fcs. Mine is 4468-8736-1675. Post your here so we can add each other. My Friend Roster is full right now, but I'll have to make room.
And also, as in how to have clan wars, there have already been some on GB. The best way I can think of as far as rules goes is by just having the leaders of both of the clans add each other. And then, the members of each team can automatically jump into that Private game since HVS was nice enough to incorporate a good friends of friends system and allow for automatically joining your friends.