One of the games I've played a couple hundred hours in is Foxhole. A MMO wargame with month long wars between two factions.
Regiments make up different functions of the game. Some do artillery, tank operations, boats, and so on.
However the regiment I played was FMAT which just does logistics to ensure the average player has access to everything in the game. Tanks? No problem. Wanna do artillery for fun? Sure.
Quite cool way to play the game.
Quite wholesome.