I'm currently rehabbing a 6 unit apartment building and am looking into doorbells and intercoms. Most multifamily intercom systems I'm seeing use phone lines, which just seems antiquated. Ideally I would install individual Ring Doorbells for each unit, but can these be connected to the same main door lock? Are there any other options like this? I planned on installing a keycode door lock on the front door so I can give access to contractors, mailmen, etc.
Maybe you are looking for something like this?
I struggled with this for a while.
I have a 4 family with shared front and rear door. I originally set-up door bells on renovation but found them to be unnecessary.
I use landlord locks and they provided me with "common door" locks that everyone's apartment key works on but no one else's doors. Therefore they only need to carry one key. I have a dummy key in a key box that can only be used on the common doors if needed.
I didn't want to put the locking mailbox bank on the front of the building, so I spoke with the post office about delivering to the back mailboxes and had a carpenter build me a "packages box" to eliminate the need for keys going out.
It has kept it simple and works in my low crime market. I find that cell phones have eliminated the "need" for a lot of things- an intercom is definitely a convenience, but ultimately for me it was completely unnecessary and would have been overkill. But, again, that is just my situation. Good luck.