One could claim that was kinda the plot of The Boondock Saints, though that was a bit different.

More like, “ok these guys back each other up no matter the outcome.” “They hooked up with a friend of their’s that happens to be a low level package boy for the mob.” “Aww. Kitty.” “Holy fuck why did you accidentally kill the kitty‽” “Kill Russian mobsters until they don’t have any influence in Boston anymore, and maybe branch out to other cities.”