The local group at Case is called Sigma Psi (
http://filer.case.edu/org/sigmapsi/).
Both Sigma Psi and Phi Sigma Rho are full members of the local panhellenic council and I believe they will both get a vote as to which sorority is picked for expansion.
The two colonies they are talking about are Omega Tau Zeta and Sigma Gamma Rho. Sigma Gamma Rho has exisited on a city-wide charter (as have other NPHC organizations), but I guess they decided to try to get a campus charter as well.