Just make matchmaking optional and those who choose it are paired together with others who chose matchmaking. Those who chose their fireteams are paired the same way. When you win a match in matchmaking you can choose to stay together [everyone push touchpad that wants to stay with the team] and if you win 3 in a row you get moved into the pool of those who chose a fireteam. Now it's no longer matchmaking, it's team making. Which is the true end game. El fin.