If you're having problems matching up, get everyone to exit to dashboard and restart the game (reconnecting to the EA servers), after 3 different attempts to get the achievement and over 6 hours of trying different things, doing this had both teams matching each other 1st time on both attempts (one for each team to win.)
1) Get everyone into the game.
2) Organize the teams so that each side has 3 players registered in their respective clubs.
3) Everyone exit to dashboard and then start the game again.
4) Xbox Live > Team Play > Clubs > Play With Club
5) When everyone is in, search.
Hope that works for you.