USE WITH CAUTION. After hearing that a fraternity member was beaten and killed by members of a rival group, a man offered this piece of advice; learn the handshake or greeting of certain fraternities.
He said this helped him out a lot when he used to hang out in bars frequented by fraternities. He said giving the handshake would get him out of potential trouble.
Of course, he added that you should not let one group see you giving the handshake to a rival group. This will just invite trouble.