How to Separate Family Plan Accounts and Keep all Dowloads

My family of four shares a family plan account, so we share all downloaded music. I downloaded the third party app ‘Airbuds’ for my friends and I to see what we’re all listening to in real time, except my dad’s music keeps being showing up as mine. But my sister who is a minor is still under a kids account and her music does not show up in my Airbuds account. How can I keep the family plan (so we all share downloads and one payment plan) and have separate accounts?