Ring intercom with Elvox 900-902

Hi there, I'm in trouble trying to install a ring intercom to my existing headset Elvox 900-902. Wirings into the headset are about: * 1 Yellow = Mic * 2 Blue = Headset * 3 Black = Common  Buzzers and Door opener are outside the headset, and both work with 12V AC. The power supply is somewhere in the building and is shared between the appartments. There is a way to connect ring intercom in this scenario ? I already have finger relays in order to convert 12V AC into any other required voltage.