It looks like it was only a one day shoot at Soldiers and sailors in Oakland.

Here are a couple more links about the shoot:
Set visit: ‘Sorority Row’ – Tuned In Journal – post-gazette.com

City sets the scene for sorority thriller

I watched them film some of this today right next to the building that I work in. The scene was set on Soldiers and Sailors lawn and involved a ton of extras.

via See and Be Seen – WPXI Pittsburgh