any wiring gurus can help me?

[PSPS]

3. The power supply is located elsewhere and supplies the whole system.

Maybe you can get the apartment manager to make this adjustment as it affects the whole system and all apartments. Another option is to look at the lobby panel where all the call buttons are. There is sometimes a sticker on it that reveals the company that installed it with their phone number. You can try calling them directly. I've found they're very helpful, although they may want to talk to the manager first before making any adjustments.