That is actually quite accurate, people of that time probably firts thought of their own "gang", their family. Then there were the similar "gangs", that you know and sometime hang out with or help in some way or another, and then there are of course all the "gangs". Between these gangs there are often fights for respect and territory, but every once in a while the "cops" or some other outsiders comes in and everyone either unites or scatters against/before the common enemy. Never quite thought of it that way.