Hi I cam across your app looking for one that can group music and maybe its easy to add it or creat an app that can.
When you DJ tango music you make playlists with 3 or 4 songs a Tanda seperated by a short piece of mucis a cortina. Here is the ideal app for that:
It works with your iTunes collection
you would have a frame where you can drag your 3- 4 songs and than move the frames artound in a playlist. Each fram will be stored as a Tanda. That way you can look for them later. If you search for a song it will show you the tandas with that song. If you add a second song it will show you the tanda with those 2 songs etc."
Maybe its something thats possible. I'm sure a lot of Tango DJ and possible otheres would be excited to use this.