hmm
after thinking for awhile,my guess would be::
turn switch 1 on for awhile, maybe about...5 mins, then turn it off again. next, turn on light 2, and leave it on, leave #3 off..
go into the room #1.
if the light is on, #2 controls it. if the light is off, but warm, switch 1 controls it. and finally, if the light is off and cool, switch 3 controls it..
repeat this proccess for all 3 rooms, and violia!