[Adult Housing] What's the best advice to deal with snooping neighbours?

I have this elderly couple who have nothing better to do than pry into my every move, when I come and go from my apartment.

The property manager says, “There is little we can do about it. Your neighbors are just opening their door to see who is in the hallway as a security measure. I’m sorry it bothers you, but we appreciate the extra security they provide.”

What can you suggest, to prevent this type of harassment?