I agree with what Carnation and 33girl have said.
My roommate my freshman yr was in Kappa Kappa Psi. I know that they did big/little and had a retreat, but that is all I heard. I never heard of them doing any service projects, sisterhood/brotherhoods and I never saw them wear letters, so I guess I would not consider them Greek(WAIT BEFORE GETTING UPSET) since they did not do the typical greek things, that does not mean they care less, it just means they weren't well known on campus and social GLO would not hang out with them as a group to do socials with-- I am not saying we wouldn't hang out with them bc they were in band.