The good news is if indeed they are used two tone paging it will not work on their digital radios either. There is likely an analog paging channel either on the system or a possibly a stand alone frequency. Many departments keep their old conventional freqs active as a tone-out but use trunking for everything else. There's a system in my area the blow the tones over the digital channel for an alert but at the same time they're sounded on an analog talkgroup to alert the station. You may want to do a bit of looking.