You will need at least 4 players in order to start a Territory Control game mode. However a maximum of 12 players are allowed to play this game mode.
The quickest way into getting this achievement is to use the host quitting method. Whoever is the host has the power to stop the game as they please. This is done by pressing the
button and selecting End Game whilst they are in a multiplayer game. The person who is the host is the one who's at the top right of the multiplayer lobby screen.
Whichever team is taking a win, simply get them to run and capture one of the control points. Once they have gained points, get the host to end the match. Rinse and repeat until everyone gets the achievement.
Chances are that the teams will get mixed up per match so I recommend you take turns in getting wins by getting the M16 to win one match, and then get the Organization to win afterwards. Rinse and repeat until you get down to the last couple players who need a win, and then focus on them to get a win.