I'm not sure of the age or the situation for one of your "girls", but if she is young, I would tell her parents, boyfriend, parents, whomever ASAP. Look up the number for your town's 24 hour suicide crisis hotline and call it. Or go to this website for steps to take when a friend is thinking about committing suicide.
http://www.stopasuicide.org/actdecision.aspx
Let her get mad at you for spread her business. At least she'll be alive to fuss at you.