I don't think I actually read this, just a summary of it. There's a story where either children or teenagers are assigned to groups / gangs / cliques. I think the idea was to reduce violence or bullying because everyone had a group that would defend them. I'm pretty sure it was science fiction set in the near future. It might have been a novel or short story, but I'm pretty sure it was some form of literature.
Details in response to Answers / Comments:
- The groups were small, small enough for everyone in a group to know each other.
- This was an intentional organization of society, it didn't arise naturally.
- The groups were formed specifically for the social benefits of group membership.
- I'm pretty sure this was written before 2010, possibly a lot earlier.
- It may have been city-scale, not worldwide, that this system was used.
- It was not any of the stories listed here: tvtropes.org/pmwiki/pmwiki.php/TrueCompanions/Literature