Generic Gang[]
The Triggermen seem to be generic "bandit" enemies rather than a specific gang from V114; they're essentially mob-themed raiders. I've seen them in Scollay Square and certain raider hideouts (like the Robot Racetrack) in urban areas. Best guess, based on the dialogue from ghoul members, is that they're wasteland "mob families" founded by pre-war gangsters who survived as ghouls.