Frequency of a sensor must match the frequency of the module however, each sensor sends out a unique identifier. This identifier is programmed into the module. I believe there are only two frequencies used by vehicle manufacturers, 315mhz or 433mhz.
Example, if you have two 2015 Silveradoes parked next to each other, the tire sensors are all on the same frequency; however, the computers in each vehicle only recognizes the identifier of the sensors that were programmed to the vehicle.
Years ago, we actually programmed the sensors from two tires of one Hummer H3 (A) to another H3 (B). Hummer A still had the four sensors programmed into the system, and Hummer B had the sensors from Hummer A programmed along with two sensors on Hummer B. So you can program a sensor into more than one system, but you could not program more than four sensors into a system; it was limited to four sensors. Spare tire was never monitored.
Trailer: Lifted 228BH, heavy duty springs and Yokohama tires
TV: 2016 GMC Sierra Z71 4x4 CC, SLT
Spare TV: Two Alaskan Malamutes
Living somewhere in ID; previously lived in Moab UT; previous to that, don't ask!