I don't know if it is fair or not. It seems like they took the initiative to get housing. Why don't the other two sororities try to get a house off campus? You could just rent a house, not everyone has to live there. My school is currently building greek row, so obviously we didn't have greek housing unless each group sought out their own house to rent near the school, but off campus. Some of us did it, some didn't. Having a house definitely helps during rush. I know that this is not what you want to hear, but, I think that if the bar is raised, you have to jump up to meet it...
I hope that everything works out though...I can't believe that group can have a pretend house and have alcohol though...their national and their advisor must be really laid back!