If even a fraction of those antennas are transmitting at any given time, which you can arrange simply by having the network poll them, all you need to do is wander up and down the hall with a TinySA or something similar. It will be almost ridiculously obvious where all the RF racket is coming from.

Even before doing that, a handheld Yagi in the parking lot will easily narrow it down to a couple of floors in a specific quadrant of the building.