Adding categories for musicians who play non-conventional primary instruments

Is there a way to include categories for musicians who play instruments other than the guitar, bass, drums or keyboards etc? For example, those who play strings/horns?

I don't think tehre is, but you know what? THERE SHOULD BE

So it seems like so far, they've been classified under composers, which currently adds categories that don't make sense to the artists page. Take a look at the Joshua Bell page as an example.

I think it makes sense to add these. Seems like creating a role page per instrument would be cool.