To add a little to the discussion, I'd point out that in neither FRS
nor MURS are repeaters permitted. And given that your crews may not
be in close proximity to one another, it does sound like a repeater
would be a sensible addition, mainly because radio doesn't penetrate
through mountains all that well. Your best bet looks like GMRS,
which, although licensed, can be had for fairly cheap, and you really
only need a single license for your entire organization. Each station
needs to mention the license ID on communications, and you can
differentiate between stations with a -1, -2, etc. My GMRS license is
long since expired, but it was something like WQFE722, so the stations
would be WQFE722-1, WQFE722-2, etc.
You don't need specific line-of-sight to the repeater, but it does
need to be accessible without the signal trying to go through
mountains.
--
Tilghman