If everyone is limping and I am in position, I try to limp if I want to see the flop in a cheap way or if I don't want to scare them away (it depends a lot). But these guys are probably donkeys that want to see every flop and try to hit a strong hand, like a three of a kind or a flush.
To play against them, you can't
bluff, you can't scare them with 2bb or 3bb in a raise (when I was donkey, I always got bored when I limped and someone after me raised to a few more chips; I was not understanding why other players were always doing this and I always was calling the small bet). You need to punish them at the pre-flop. You will try to make expensive bets, because they want to play, in the cheapest way, with every connected or strong hands (suited cards, pocket pairs, close numerical variations, Ax and Kx hands, etc.). I don't have to explain that these hands will not be profitable to play everytime in a long run.
And this is your advantage, your tight range will destroy their lose ranges (at mostly time).
Also, please, remember to think twice when they go all-in on pre-flop, because they could have pocket pairs (specially JJ+) or other Broadway hands (specially AQ+). Be patient and you will be successful in the game.