That's ridiculous. If you bring a weapon into a weaponless confrontation, you become the bad guy. Now, if you think you're tough and able to fight, you probably can't. But, now here's the fun part, they probably can't either. That's why they hang out in such a huge pack. That's also why they get courage when there's someone on the ground.

Pick the leader. Either get in his face and talk some trash (for that matter, talk trash to all of them). or Mess him up. If you mess him up, they'll flee like little cowards.

My advice to you is to stand up for yourself and your friends. Don't fight if you don't have to but draw a border. Don't let them touch you. Tell them that they have no damn right to put their hands on any one of your friends and then tell them to get the f out of there. The worst thing that happens is you get your bottom spanked. Then, you can hunt them down one at a time and hand them their bottoms on a silver platter. Otherwise, stay out of trouble.