I have never been to coledge, but here are some things me and my freinds do when we need to take our airstoft guns to a public place before going to a game. Often we got to a local church on Sunday, then afterwards go to a freind's house to play. Obviously, we don't want people knowing about or seeing our airsoft guns as they could easily be mistaken for real steel.
The most effective tequniqe we've used is to put them in guitar cases. We've found that you can fit a full size rifle (M16, AK47, Bolt-action sniper rifle) and a submachinegun, or short shotgun with no stock or a folding stock in the main compartment (along with some ammo), and 2-3 pistols (depending on size) in the small pocket. the cases can be locked easily and you can buy hard cases that are difficult to cut through. We keep these with us though, which would be difficult for you. Perhaps you could screw a hardcase to the bottom of a box-spring matress from the inside (bring your own so you can still sleep comforatably on top of one without a hole in it). Or simply stuff a soft case in one.
Also a metal breifcase hidden in the same manner would be very difficult to cut through without a torch. And I think somone would notice a torch burning in a dorm, or hear a saw cutting the wooden bottom out of a matress.
Hope I was a little helpfull (though I doubt it)
