Carman,
As far as the bruhs go there are no official affilliations with any sorority as sisters. As I understand it the only fraternity that has a brother-sister relationship are the Sigmas and Zetas.
This relationship was only established through natural need for the organizations to have male and female balance amongst themselves. We(all black greek organizations) started to just pair ourselves up whichever way best fit.
On my yard the Omegas did not discreminate against any of our sisters. However, we did maintain the close status quo Que-Delta association. But in my opinion we just as close to the AKAs, Zetas, and the Rhos.
I hope that answers your question, if not hit me up sometime at:
Gypsyred