Emory has a great Greek Life Web site, including a timeline back to 1869! So you can find out what groups have been on campus and when they left or came back etc.
http://www.emory.edu/GREEKS/index.html
My parents were both Greek at Emory, my mom was a founding sister of Chi Omega when her local sorority affiliated in 1959. It would be great to have her chapter back.
I also know that there was a Delta Gamma chapter that closed in the mid 90's. The Atlanta DG alums are an especially strong group that could support a new chapter.