I had made a previous purchase of the Plex app under my apple ID well before Family Sharing started. I'm part of a family share (not the organizer). My apple ID shows up as sharing apps on the other phones. When I go to Plex in the appstore on a phone logged into a different itunes account, but one that's in the family share, Plex is showing up as a $4.99 download. How do I download that for free on the other phones in the family share under their IDs?