Have you locked the door to only allow guests?
I only get these options...
-Allow/Disallow Only Me
-Allow/Disallow Pets
-Allow/Disallow Lot Visitors
-Allow/Disallow All Sims
-Allow/Disallow Household only
-Allow/Disallow Roommates
Right now I have it set to "allow household only", but it's really annoying having to turn it on and off all the time when I invite guests over. I don't know what the "lot visitors" option is, but turning it on/off doesn't stop the other apartment sims from intruding in my apartment. Also, there seems to be a bug. Sometimes when I have it set to "allow household only", my roommate cannot get in. They stand there with a bubble that says the door is locked, but once in a while, they can go through. Weird.