There are two international sororities that come to mind that may fit your needs. They are Beta Sigma Phi (www.betasigmaphi.org) and Epsilon Sigma Alpha (www.esaintl.com). Neither of these sororities are members of the National Panhellenic Conference (NPC), the National Pan-Hellenic Conference (NPHC) or any other umbrella group. Their chapters are almost exclusively "community-based" which means that they do not necessarily have collegiate chapters. Epsilon Sigma Alpha does have a few collegiate chapters.

Good luck in your search for sisterhood.