"Rival gangs" refers to groups of people who are in competition or conflict with each other, often engaging in activities that are considered illegal or violent. Full definition
This mass killing of rival gang members was attributed to Capone, although formal charges were never made. (bookbrowse.com)
But at age 13, when she was incarcerated in juvenile hall for using marijuana, she found herself closing her eyes and letting her guard down in a room full of rival gang members. (wuwm.com)
The name nicely ties in to the segregated cliques that have formed in the Los Angeles area, whereby ethnic background and skin color marked the dividing lines of wars between rival gangs for territory and dominance of the community, which spilled over into violence in the schools when the different cultures of the area are forced to go to school together. (qwipster.net)