The owner of my apartment has hired a realtor to sell it. According to the answers in the above linked questions the realtor can access the apartment at will. This realtor is wanting other realtors that he's somehow affiliated with to show the apartment as well. Are these realtors also considered agents of the landlord (and thus have legal access to the apartment)? It sounds like there will be several people coming and going at will to show the apartment.
Edit to include more information that I've just been provided: The realtor appointed by the owner is part of the city Board of Realtors, and the realtors all cooperate in showing properties. The realtor tells me that the "listing agreement" with the owner of the property "includes the allowance of showing to the other professional realtors". It sounds like there will be a lot of realtors coming in and out.