In Charmed season 1 episode 11, Macy broke the news to Maggie and Mel.
In the previous episode of The CW’s Charmed, the Charmed Ones rescued Harry from Tartarus, and Macy discovered that she and Maggie share the same father.
The director of the Hilltones, the college’s acapella group, went to Athens and found an old pitch pipe.
Jada already knew since they had an empath, but she felt that Mel would come to understand their point of view.