You follow your heart.
I was in a similar situation. When I rushed, there were 4 NPC sororities and a brand-new local that had just been founded the previous semester. The president of the local gave a short speech during orientation, and they had an information table during formal recruitment where PNMs could stop by, pick up the local's rush schedule, and chat with sisters in between parties. Then, the local had their own rush following Bid Day.
I got to the end of round 2 of FR when I realized that although I was very sold on the idea of sisterhood, none of the 4 NPCs was right for me. So I withdrew from FR, rushed the local, and found my home.
How far into recruitment can you go before you have to commit yourself one way or the other? I'd imagine that you could go all the way through pref if you wanted, and as long as you didn't sign a pref card and get a bid, you could still rush the new sorority. So I'd advise you to go into FR, and if you find your home, great... and if the fit isn't there, visit the new sorority.
Good luck with whatever you decide.
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