Sqad - // Girls by and large are bitches.
Cancel her trip and tell the parents of her "mates" why. //
I have three daughters, and all had their 'moments' in school relationships.
The simple fact is, as their dad, I was not, and am not blind to the more undesirable aspects of their characters.
But that does not mean for one moment that I would accept another parent telling me that my daughter was a ***, or anything similar, and I doubt any parent would.
There is nothing except grief to be gained by being overly honest with the parents of the protagonists, it can set unpleasant ripples in progress which can last long after the girls have either made up, or simply moved on with their lives.
The golden rule is - keep out of the details, say only what is needed to sort out the situation.