The OP describes a real, and unfortunately common, problem. It is a blight upon our communities. It must be addressed ASAP. I know the Rabbonim shlita try hard addressing the Tznius Crisis in our midst, but this issue needs to prioritized.
We need to insist to the Beis Yaakov’s to properly teach our Bnos Yisroel proper street behavior. Not to let us parents off the hook, as we have primary responsibility.