Each location will have an intercom system. There will be a single telephone number for all of the intercom systems to reduce cost. You can add the number into your contacts to let you know that the door system is being used to contact you. When your button is selected, there will be a telephone call to your telephone number. You would either answer, or let it go to voicemail. If you answer, and will want the visitor to enter, then you will select the * key which is next to the 0 on a numeric keypad. If you don’t answer, then the visitor will be forwarded to your voicemail system where they can leave a message for you at your voicemail. This means you can use your regular voicemail system for your telephone.
This is the best solution that I could think of. An alternative will be to have an intercom panel in the unit, but this might be a disturbance if someone is trying to buzz you in at 2AM because they don’t know which apartment to buzz. You are not allowed to let strangers in the apartment. The only exception is if you are expecting a delivery, and then you can let the delivery driver in.