Team Awesome

hi my solution is a little bit easier i think.... went on last night to get this achievement and you only need you and one other.

load up the game and go into multiplayer and you enter a lobby by yourself. then invite your friend and you will both be in the same lobby from here set up.

Team event
race

when the game loads you will either get race-off or domination
and because not many people play this section anymore you should be the only two in the lobby let the game load and just take it in turns to win.
when the race is over and it starts loading back to the lobby the achievement will pop for which one won the race

hope this helps