More than usual for GFS crew this applies too:
I don’t know anything about them. The abbreviation may mean „GOODFELLAS“ and they are from NRW, probably from the area Essen. I don’t have hard facts due to the members of the crew. All I have is the names of writers, which are quoted due to the pieces I found over the time. And here they are, but, as always, no guarantee of completeness and no warranty of any kind!
It’s quite possible that I’m completely wrong, because I find it difficult to impossible to distinguish between GFS and IHS. The tags are associated very often and (for me) the style is very similar, which leads me to the guess, that the members of both crews are very close friends. At least they often work in close cooperation.