boston ems radio procedures - ????

not sure what boston ems radio procedures are these days - but they
could do this

462.975 R - main channel - normal ops - day to day - 24/7/365 -
dispatch to calls - arrival at calls - ( ops at calls are on a simplex
car to car channel ) - enroute to hospital and at hospital on this
main channel

462.95 R - 2ndary channel - longer non urgent messages - admin type traffic

boston ems typically has 20 to 30 ambulances on the road / in service

so - for a major incident - they could just tell anyone not assigned
to the major incident to switch to the 2ndary channel - they could do
that via mdt and via text - ( and via a short verbal radio message or
maybe a special tone signal on the main channel)

they also have 460.525 R and 460.55 R and 453.775 R - but unknown if
they ever use those channel nowadays