Each "set" (Rollin 60s for example) is independent, and may have their own alliances with other sets. Some of the bigger sets have cliques. Back in the 70s when it first started, all Crip gangs were intended to be aligned.
Rollin 60s is the biggest black gang in LA. I think LAPD has them numbered in the 100s, but I don't think they seperate "active" members.