Your interpretation of what you THINK you can do and what you lawfully can do are like night and day.. I'm going to be harsh,, your post clearly shows you are not up to date, or maybe of aware of Fair housing laws or your landlord tenant laws.. the potential for your rental business is just one showing away, from being in a lawsuit, the defense of I didn't know does not apply..
I'd try and answer your initial question.. but until you understand the familial status of people trying to rent your apartment and what that means, your not ready to take or show your apartment to ANYONE,, yet ,,until you know more about the rental laws, is my personal opinion.
- Discrimination based on race, color, religion, sex, familial status, or national origin in the terms, conditions or privileges of sale or rental of a dwelling.
familial status,, is not something you can discriminate on,, .. married,single, divorced, separated, unmarried, man and man, woman and woman or man and wife or blah blah.
google Fair Housing Act.. and then Google Rental Criteria,, so you can start fresh with your rental business, or hire a PM.. (property Manager)