Well, again you know that you can no longer pick and choose her friends. All you can do is balance out what they are telling her. We may not like it, but we are living in a "tell all" world. Reality shows abound, all manners of snapshots on myspace for the world to see, and blogs where we tell our entire lives to strangers. This is the world out children grew up in. So the idea of keeping your sex life private is a personal choice and might be considered by many to be an antiquated way of thinking. I personally am not free with my love life, but know more people who are than aren't. Remember when oral sex was just not something that was talked about? And no woman would ever admit that she did it? It's common language now, (giving someone a "Lewinsky") and is not the dark secret it once was.
My Native American grandmother used to tell us stories and she told one about a bow and arrow that related to parents raising children. She said that the hunter is the parent and the arrow is the child. The hunter could be the most skilled hunter in the woods, but when she/he shoots that arrow, there's nothing she/he can do but let it find it's mark. It could be windy, raining, snowing, etc, but if she/he is a skilled hunter the arrow won't fall far from the mark. You have to believe that the values you instilled in her thru out her childhood will stick with her. Sure she may stray sometimes, but most times she will always come close to the mark.
As I said earlier, you can bad mouth them, but she spends all day at work with them, and it will probably only make her take their side or feel bad that you are bad mouthing them. This is your time to give your opinion and drop it. Ask her, "what do you think you "must" do to keep a guy?", "What things do you think are most important to a man and in a relationship?", "What things are important to you in a relationship?", "Is there anything you wouldn't do to keep a man?".
Think about setting up a girls only night, once a week or every two week (once a month if time is tight for everyone). Use this as a time to catch up on whats going on in everyones life, as well as bring up topics of interest. If the dates are a hit, you can set up subjects ahead of time so that everyone has a chance to think about it (ie; anything from what it will mean to have a woman or a black president, to what constitutes a poisonous relationship, to how women in abusive relationships can help themselves, views on abortion, views on raising children, views on drugs, etc). Do what her friends are doing talk, and your talking can balance out some of the garbage she's getting from others.
I don't mean to make you feel hopeless, because you probably have more power than you realize, it's just theres a thin line between nudging them in the right direction and pushing them in the right direction, all a push does sometimes is get a push back. Think about how to say something without saying it, how to make her think without being parental, and know in your heart that most of the time, she will make the right decision.
Let me know if you want to talk more.