I think there should be stores with an iron cage at the front where the packs of wild children can be housed while the adults are shopping. I would pay a premium to go to such a store.
I've seen what this rant is about, and yes, it's a peeve of mine as well. Not so much the mommy groups, but the children that run around the stores like a pack of wild dogs. All I ask is that moms keep their kids under control. I never thought a trip to the grocery story would turn into kid-style bumper pool or some sort of kiddie obstacle course.
The picture's a bit grainy, but those are cages in front. They come in really handy. They even will provide you with a padlock at the front desk.