[aopinthesky]

While I don't exactly get your point, I am going to answer your question as best I can. My sorority (as probably most NPC groups), celebrates and encourages the diversity of it's members, and welcomes anyone who embraces their ideals. I have been a member for a long time, and that idea of a diverse membership has never changed in the 27 years since my initiation - although it is a more prevalent subject now.
I have no first-hand experience of having a person of another race in my chapter, but I think that if you choose to be a member of a particular organization and if you stay loyal to it, then you must accept your sisters (or brothers) for all the ways they contribute and look past the obvious differences.
Anna