There is a web site explains the steps involved in getting into a sorority, generally speaking. Here is some of what it says about recommendations:
"Some schools, mainly competitive Southern schools, require recommendations for someone to have a shot at joining a chapter. This is never stated outright. Generally recruitment information says something along the lines of recommendations are not required at XYZ University. It is the responsibility of the chapter to obtain a letter of recommendation for a potential new member if the chapter requires one. What this means is that if you are totally outstanding, the chapter will find an alumna to write a rec for you. But if you dont wow them, lack of a recommendation might result in you getting cut. But why make it come to that? It is much easier to obtain a recommendation for every chapter at the college you will be rushing and have them submitted long before rush starts. Many cities have a Panhellenic association in their town that you can contact to get recommendations."
To all of this I say, to each his own. I found the web site while looking up an acronym - I saw someone referring to a PNM, didn't know what they were talking about, and googled. Here is the web site, in case it is helpful to anyone.