Gang Banger Achievement

In order to do this you will a) need at least five survivors on the survivors board, and b) need to have upgraded the first three tiers of Mechanic and Smarts for the +2 Maximum Posse Size, which they both give you (1+2+2=5). Once you have that, you can either roll through the game trying to keep your survivors alive, or wait until you have at least 5 available to follow you and pick them up at a board all at once. You'll probably want to invest in maximum life as well so your followers don't die so easily (if they die, they stay dead unless you have this ability).