if the point of the congregating is to attract boys, then boys congregating to attract boys should also be an issue. in my opinion, there is nothing inherently wrong with girls getting together or walking around or whatever.
if you are in a situation where you can not change another persons actions (which is very often the case) then it becomes YOUR obligation to get yourself out of the situation. if the problem is that you pass them on your way to and from learning, and on your way to and from shul (just out of curiosity- if you are inside the entire time, how do you know that they dont leave and come back?) then perhaps find another way to get to your destination. it may be a way that takes a little bit longer, but it will help you to avoid the situation.
you may (or may not) be right that girls should not be standing around shmoozing, but there is something that YOU can do about the situation. shmiras einayim is a mitzva for you, and in this case it would seem that you might have to go out of your way to do it.