There are several ways to handle the Intercom directory. It is at the preference of the resident or Building Admin.
You can create an entry with just Unit #s, Unit # + Last Name, Unit #s + First & Last Name, or just First & Last Name, or mixed. That is the beauty of our system.
For each entry you can link one or many residents. If there is one entry then all residents tied to that entry will receive a call until someone picks up.
If each resident that is living within that Unit wants to have their visitors contact them directly and not everyone then I would advise the intercom entry to be "Unit# + Last name"