Apple has implemented multiple kinds of sharing for media—apps, music, audiobooks, movies, and TV shows—but imposes limits across a few directions, ostensibly not to reduce piracy, but limit the reach of any particular purchased item. Some of this–maybe all of it–is at the behest of copyright holders that require Apple to meet certain terms to offer the media at all.
If you BYOM (bring your own media) to any of Apple’s software that manages, plays, and shares it, you’ll feel these limitations, depending on with whom you share and how you’ve set things up.
The better alternative if you have a lot of your own stuff to share among a family, including on the go and geographically dispersed? Plex.