I'll be honest, it helps if the opposing side is either waaaaay undermanned or full of fail. But with or without that, first thing you need is a small group to run up and cap stables. Once you get that everyone will have to be very mobile to not only achieve and maintain a five cap, but also to make sure to stem off any offensive attempts by your opposition.
It's possible, but it's part luck, part imbalance, and part speed that makes it happen.