Rural Metro Ambulance could be using Cass County fire dispatch to provide service to all the Cass County fire departments. In Indianapolis they used to be on 155.265 and that frequency went silent .Also the same for 155.235 that used to be Myers Ambulance that was bought out by Rural Metro for Johnson County. I know that Rural Metro does provide service to Madison County. I hear Rural Metro 410 and 411 all the time on Madison County fire dispatch 155.070 Repeater.
Johnson County they are dispatched via SAFE-T By JCFD. Heard them and SEALS get dispatched to a multi car pile up/rollover today. SEALS pretty much stole Medic 93's (Rural Metro Unit) call by being closer, so 93 got cancelled while en route. If R/M is on an SMR, it would have to be JES & Sons, or Cardinal, whether its the conventional Repeaters, or LTR/NexEDGE TRS's. In Cass, they also are dispatched via County Fire on SAFE-T/VHF. Madison they are on the County Fire VHF, Hendricks County also on the County Fire VHF/SAFE-T.
Pretty sure they use a combination of cell and ERS Two Way ConnectPlus wide area system for company communications. Crews that respond to emergency calls have radios compatible with those used by the agencies they work with.