Spot on reply, but definitely on the other opposite of the spectrum (ha! pun) from yard duty on FRS radios. I would have loved playing on a system like that.I installed a 5 site Linked Capacity Plus system for a large school district several years ago.
Just to reiterate OP's original request for the sake of the thread, since even I got sidetracked into thinking he was asking to fix school comms. He has 6 different schools, each with their own radio "solution", and he was looking for a single radio that could do all 6 sites in one radio load, so he doesn't have to carry 6 radios. It sounds like just his problem, the schools aren't complaining about comms, nobody else seems to have the need to operate between sites (yet). He just needs to find a radio for himself that can likely do it all, as well as get the programming info from each site and get it into his new radio. But of course, once you peel off the first layer of the onion, there's a lot more.
Refocusing on that, this is likely a 2-3 hour billable job at a radio shop, take all 6 radios in, request them to read each radio and create a report of what's programmed in them. What you do with that info next is up to you, either have the radio shop get you a radio that can do all 6 sites, or share here or you can message me directly, and we'll likely point you to a dual-band DMR-capable radio to buy, the software and the cable, and you can play from there.