If a basement room of a house is rented to a female gentile, and the corridor to that room is shared, is there a problem of yichud if a male resides on the main floor with access to the basement? What if a female Jewish girl occupies a second room in the basement, is there still yichud with the male upstairs now that the are 2 females?
My apologies that it took a while to get back to you.
Regarding your question, it really depend on the setup of the house, but in general if the tenant has a way of keeping herself locked inside that the landlord can not go to her then it would be permitted according to numerous authorities. However if the corridor has no lock to it, and the landlord has access to the corridor, then when she will be in the corridor it will be yichud. Therefore it really depends on how the house is set up. (Even if the setup of the house can potentially be yichud, when the man’s wife is at home or may return home soon, that would protect the two temporarily from a yichud situation.) The fact that there are two female tenants there will not really help because one male may not be secluded with two women.