Sub7an'Allah, I just keep on hearing(and seeing) stories similiar to this(although, i think your situation might be worst...to an extent).
Sis, insh'Allah you never get influenced by this, and don't ever be shy to stand up to what you believe in. If some guy talks to you or erm..does something? innappropriate, you can explain it to him why YOU don't do such things, and why such things aren't permissible.
They might say" But so and so does, it, why not you?"
And then follows the explanation. I've had to do this pleeeenty of times. Dear Lord. but, never get tierd of it, it's important that these people see that even if "everyone" is doing it, doesn't mean "it's O.K".(that was a quote I used many times

)
As for how you can help your muslim sisters out...awh that is very noble of you

, if you feel you are capable, try to speak to one of these girls, preferably if you have a friend among them, not in a critical manner, but in a way of incomprehension. Ask them why they behave in such a way,then tell them that your door is open to them anytime

.(it works...not with everyone, but it works!)
Lastly, make Du'ah to Allah(swt) to guide our muslim bros & sis...it truly saddens me when I see/hear such things, to an extent where..where I kind of get depressed at times(when I see people I know and love behave in such a way)... in the end,don't judge,that Allah(Swt) will do in its proper time,and be there for anyone who needs your help...
Remember, no one's perfect,everyone makes mistakes, and Allah is Forgiving.
