I think this is really a question you need to be asking your office of Greek life. At my alma mater, the local sorority was a fully participating member of the local Panhel, and while NPC didn't have a relevant policy, our campus regulations treated the local just like any of the NPC organizations. The new colony would not be allowed to offer you a bid.
I looked up the PH Constitution at the local college. It used to say that women had to wait a semester before pledging the nationals if they were in that local and vice versa. That's not in there anymore and it was probably challenged successfully...I mean, how were they going to make that rule stick?