[AlwaysSAI]

As 33girl said, it really does depend on the school you attend.

While a collegiate, I was also a member of Phi Sigma Pi, though it is not a social organization, it did divide time.

One of the founding members of my chapter was also a Chi Omega. And, one of our chapter advisors was a Chi Omega and SAI, though I don't know which one came first for either.

I joined Phi Sig after joining SAI and my sisters did not treat me any differently, but there are some schools where SAI functions much more like a social sorority. On those campuses, it may not be as common or accepted.