I believe that our NPC agreements state the same (that all surveys must be viewed/approved by HQ before submitting any type of information).
Katy, if this is for a large scale project (like a thesis) you might be able to get lots of information by contacting NPC headquarters at
www.npcwomen.org That site will also list the 26 NPC sororities and give you links to each group's website, which will give you contact info for their HQ.
What kind of project are you doing?
PsychTau