Well, if the Fireteam was rated on a simple system of having gone Flawless, and each fireteam member that has gone Flawless is +1 to a group rank, then there would be 4 grades of Fireteam; Rank 0 Fireteams of 0 vs 0 (nobody on either team has gone Flawless), 1 vs 1 (one member on each team has gone Flawless), then 2 vs 2, and finally Rank 3 Fireteams of 3 vs 3. Then, the system just needs to prefer matching like rank to like rank.