Most Helpful Girl
Frolic into the land if "I don't give a flying f*** about your opinion." It's an amazing place.
Seriously though, If they don't stop make it very clear that they're it's a form of harassment and that if you were a woman you'd get away with it the way they are. Don't be afraid to storm over to your boss. Don't be afraid to jab your finger in their faces and tell em to piss off.
Usually, when you don't give a fudge you become attractive because you stand out for not caring. You'll find a woman if it's important to you right now. If it's not then I grant you a free ticket to the land of no f's given. You can take a train out in a few years when you are interested :)
Most Helpful Guy
I mean if you work on confidence and find someone who you can make laugh and have interesting conversations with then maybe ask her out to coffee (/lunch/or something like that) then you could shut them up. It's really not easy, you just gotta keep trying and learn from mistakes.
Otherwise, I would just try your best to ignore those girls to the extent you can.