How to not be so close to your bestfriend?

just distance yourself a bit, and stick to your guns. BE FIRM! tell her she cant keep talking about people if she expects people to still wanna be around her- it aint gonna work if she keeps talking about people within the group. Next time youre gonna have to partner up, pre plan with somebody else and tell her sorry but you promised ages ago that you would be their partner so she should partner with stephanie maggie or hayley but you can be partners with her next time.