On a dating site I recently saw they used a permission system that allowed the listing owner the ability to control who saw thier pictures. Permission is given by the user asking for permission from the link owner and the link owner just clicks a check box that allows the user access to their pictures.
This is like a "group" that the new user is added to when the link owner allows access.
This is like a "group" that the new user is added to when the link owner allows access.