These guys are bullies, plain and simple. Most of them probably grew up without a father figure in their life and it shows.
You need to show them you're not afraid of them (or anything.)
Find a good tattoo/piercing artist in your town. Ask around for who's reputable because an infection is serious business.
Ask him about getting a glans piercing. The glans is the tip of the penis. It will hurt, though there may be numbing spray. It will be like a little metal rod through the pee-opening with two studs on the end.
Next you'll need a bike. A basic mountain bike will do but make sure the seat is adjustable incase your manhood (penis) isn't long enough to reach the front tire.
When you encounter one of these gangs whip out your pee-wee (penis) and let it rub on the spokes of your spinning bike wheel. This will sound like a motor bike (motorcycle) and will startle the thugs/bullies.
The vibrations from the stud on your glans (penis tip) will quickly make you climax/cum. Anyone who sees you cum will be scared of you and your penis tip.
This may sound crazy, but I'm serious. It's gotten me laid twice so far.