I wouldn't tell the boss what the others have been saying - that will get very ugly very fast, and could hurt your other work relationships irrevocably.
I would stay out of it as much as possible. If people say things that are blatantly unfair call them on it but otherwise try to stay out of it. If your colleagues don't like her, that's okay. Its okay for them to not like her. Just as its okay that you do.
If they start to moan about her, change the subject.