It depends on the motivation levels among feral gangs. My guess is they will be trying to avoid casualties. They may rush a home, but if any of them get shot, why would they not seek easier prey? You may see it in a movie, where a gang of twenty attacks the hero's family and keeps coming after ten are dead, but my guess is that won't happen. Have you ever watched a predator attack prey that fought back? I have (recently), and it's amazing how even the risk of injury will keep a larger, stronger predator at bay.
That's my experience watching wildlife. Let the butt of a pistol show and everyone remembers appointments they are late for.
/johnny