[aopinthesky]

Christina,
If your campus has other NPC groups, you will need to start with your office of Greek Life or the Panhellenic Office on your campus. They will have to approve expansion before you contact groups about affiliating. If all your groups are local, you may still need to discuss "going national" with someone at your school, but you can contact the National Panhellenic Council who will then put something in their newsletter so that any NPC group interested in expanding to you campus will know about it. Good Luck!