Avoid meeting her friends in the first place. Nothing good can come of it.
You have to meet her friends. Gives you a good idea of who she is. It'll also allow you to keep her on her toes if you randomly ask about one of her friends from time to time. Especially if her friends are solid, good-looking women. You known d@mn well her friends are constantly asking her about you. You know women don't have much sh!t to talk about other than the men in their lives and other dumb sh!t.
Don't ask her about her friends, regularly. Just throw it out there from time to time. Women are insecure. Always trying to one-up their friends. If you have your sh!t together, she'll naturally try to keep you away from her friends after a while! Especially if her friends aren't 100% solid and trustworthy women.
The key is to limit the number of your friends she gets to meet. You don't want her getting too comfortable with your friends. Because, she'll use the same sh!t against you to test you.
Women love to try sh!t to get under your skin...to manipulate you.