I'm trying to find a door intercom system for use in a building with 2
access doors. The intercom has to go to 3 different rooms. (In other
words, I want it to have 3 handsets, each with 2 door release buttons
on; the door intercom to have 3 call buttons on)

I am struggling to find such a system, does anyone know if one exists?

(I know I can do it using an interface to the phone system, but looking
for an alternative stand alone system)
--
Tim Mitchell