In my experience, the General Contractor has a list of frequencies and PL codes for each project. These are typically UHF itenierent freqs and each contractor or type of contractor has a channel reserved for them on this list. Typically, each contractor may run FRS/GMRS/MURS for their internal crew comms onsite or just run on their assigned channel from the GC. However, some people tend to get upset when 5-20 crews chatting on the channel in a language they dont understand (which is why the supervisor or crew lead will carry the radio on the GC frequencies and then their FRS/GMRS/MURS radios). TT