Bad credit person still denied even with co-signer tenant/room mate?

I live in this condominium for about 7yrs and 2 years in the present unit. I have to move in another unit/rm and want to have a room mate. My friend supposed to be my room mate have a bad credit when they require for a background check so the condominium ociation denied her to live in the bldg. and be my room mate even I co-signed for her. My realtor and the owner of the unit doesn't really care but the condominium ociation decide. I want to know if this is right and accordance to law to deny someone even with a co-signer that accept full responsibility. What agency I could ask for help to intervene or complain. I live in Atlantic City, NJ.