What the existing connection tells
A ringing call that keeps ringing on every screen and every phone at the same time can be annoying. At the same time, you don't want a call to end up in an unused room.
With multiple intercom posts, the intercom becomes more convenient in a large house or building, as long as all devices have a clear role.

A ringing call that keeps ringing on every screen and every phone at the same time can be annoying. At the same time, you don't want a call to end up in an unused room.
Inventory rooms, users, and moments when a call should arrive. Also look at the maximum expansion, cable routing, and power that the chosen system supports.
Establish a main post, any secondary posts, and app accounts with a purpose. Choose a call strategy that fits the residents instead of letting every device go off by default.
Test from the external outdoor station who receives the call, what happens when one user answers and whether door opening works from any allowed device.
That depends on the system; test the desired situation beforehand.
No. Separate usage rights from settings where that is possible.