I'd suggest the next time someone touches you, for you to be carrying something large/bulky, make a turn and wack them in the head or ear or drop it on them. Call it an accident.

You could also pick a fight with one of them. I suggest someone smaller than you because it is important that you win the fight. It is like what they say in Fightclub, most office people are wimps and will go to great lengths to avoid an all out physical fight. It is important that you egg them on to make their disgrace count. While not actually bike related, I have been trying to find someone at work to fight or wrestle with for the last 7 years; no one has taken me up on my offer.