Maybe this would work its simple, for restaurant press 1, point this to virtual 250, assign 250 to any button on phones that should ring for the restaurant, program that button to ring. For bakery press 2, point this to virtual 251, do the same as above.
You can setup the virtual so when you press its button it will give you system dial tone or you can program it with automatic trunk line seizure.

We get old too soon, smart too late