In order to boost this you will need 3 other players - Once you have that create a private/Friend's only lobby and invite everybody in.
I don't think settings or map matter too much but I had it set to Deathmatch.
The person going for the achievement needs to be on Team 1 and everybody else helping needs to switch to Team 2.
Start the game and just to be safe I had the person going for the achievement (Team 1) build a few houses and after about 2 - 3 minutes everybody on Team 2 resigns one by one.
The achievement was a little delayed but eventually popped on the victory screen. One of my friends had to do it twice for it to eventually pop but we managed to get it for all four of us.