How is it possible for a girl to be initiated into two sororities?

[nyapbp]

I also remember a situation I read about in the late 1980s, early 1990s when a woman transferred from one midwestern campus to another. She was initiated into an NPC group at the first campus. She transferred to a university where her group did not have a chapter. She went through recruitment again, and was initiated into another NPC group. During an intercollegiate sporting event, some women from her first campus saw her wearing letters for the second organization. Much correspondence ensued and she ultimately resigned or was dismissed from the second one (or maybe both, that part I do not recall).