There are systems used by first responders that allow for radio basestations to be connected to landlines to run to other basestations. This allows you to create more coverage area for your network. The radios run a trunked system that is more like how cellphones work than how something like CB radios work.

This is why things like ARES (Amateur Radio Emergency Service) is important for disasters where centralized systems aren't working but long range, simplex (decentralized) nets can still operate.

Two way radios can often connect to the telephone network through a bridge at the radio repeater

What he said

I have an ancient book on Private Mobile Radio. It has a section on using leased lines in it