The important thing here is to take this a compliment and a sign of her love, rather than get annoyed that her entire girl gang knows way too much about you and your relationship. The thing is, women won't do more than mention you in passing if you're just some guy she doesn't care about. It's when she starts sharing intimate details with friends that you know she really cares.
She cares so much that she has to source second and third and fourth opinions about certain things in the relationship. She wants her friends to help her stay on track and she also wants to share the exciting details with them. You're such a big part of her life that she can't not talk about you. Just try not to disappoint her, because you'll have her friends to deal with.