We received multiple group emails from the department secretary from April - August that had everyone cc'd on them, but they were more informational in nature.
I think in June or July, someone from the cohort sent a chain email out for us to all introduce ourselves. At that point, whoever had facebook became friends with each other.
As soon as soon of some of us moved down there (beginning of August and "duties" started mid-August), we got into contact and went to happy hours and such to get acquainted.