I have lost some bestfriends too. But that was my choice. Our friendship is no longer working out so I chose to move on with new friends. Almost 12 yrs. have passed and I believe I made the right decision. They're happy with their friends and so am I. But before you give up your friendship with them, I agree with the posts above. Try to talk to each of them individually. Do your best to convince them. If they still do what they want to do, consider to move on. They're living their lives, so live yours too. Good luck.