We have both DDs (aged 6 and 3) in the same room and the way that it works now is that DD2 goes to bed first, has 2 stories then gets to put her music choice on. She is usually in bed between 7 and 7.30. DD1 is doing homework while this happens. DD1 then goes to bed between 8 and 8.15 and chooses her music to listen to. DD2 is generally asleep by this time.

Alternately if for some reason they aare going to bed at the same time they both get stories and have to agree on the music.