Lehava, it has to be initiated by the women. I live in a town/culture where using the term "girls" to refer to female employees can literally lead to legal action against the man who said it. It all depends on the attitude of the women; there's no predicting it, and no rulebook. That's why men, at least, freak out. I am very cautious about calling women co-workers anything except "my colleague," even those I've known for years and consider myself on good terms with!