One way it has to be because all FRS's use the same MHz freq, may just not be labeled the same. My channel 10 might be most others channel 1, just need to know the Frequencies so can match up. only problem might be when you say sub channel are you talking radios that use Digital Coded Squelch (DCS) or ones that uses Continuous Tone Coded Squelch System (CTCSS) DCS and CTCSS are not compatable.