It would help if you showed what (if anything) you've already tried so we can give you specific recommendations.
However, as a starting point, I'd suggest researching supertype/subtype relationships. You can use this to model Performers, of which there are two types: Groups ("Empire Brass", "London Symphony Orchestra", etc) and Soloists ("Itzhak Perlman", "Yo-Yo Ma", etc). If necessary, you can relate soloists to groups to show an individual's membership in a larger performance group.
You could also use subtypes to model music, in which case you'll have something like a Composition ("Symphony #5", "Cinderella", etc) and a Piece ("1st Movement", "Act 1, No 5: The Fairy Godmother", etc). In this case, a Piece will have a mandatory many-to-one relationship with a Composition.
This assumes a many-to-one relationship between a Piece and a Composition. However, if the relationship is many-to-many, then I would go with one Composition table and have a resolving "Composition Makeup" table. That would allow you to, for example, associate "Dance of the Sugar Plum Fairies" with both "The Nutcracker" and "The Nutcracker Suite", but associate "Battle with the Mouse King" with only "The Nutcracker" (all of which would be listed in the Composition table).
From there, think about how to model a Performance, which is simply one or more performers performing a composition.