Hmm, not sure what the best method is to join a group of friends who are currently in a match. If I select 'join their game,' the game is full and I have to wait for free player slots, which may not happen any time soon.
If you're on the list and didn't receive a friend invite, please tell me here or send an invite in game. It's a little difficult to type in 12, 12 digit numbers without screwing a few up. Especially when they don't allow you to use the pointer.