PS3: Warhawk ribbons with two people?

I need to get the Warhawk Ariel Gunnery ribbon and there isn't a chance in hell I'll get that but I was wondering is it possible to get the eight people to end the pre-game and then ban them except for my friend and continue the game so I can get my ribbon with just me and him or does it revert back to pre-game or end the game when it gets under 8 players?