Roman numeral sorting

[lyapounov]

I know it is a complex issue, but would it be possible to have roman numeral sorted ?

Currently, I have

Concerto per violino I
Concerto per violino II
Concerto per violino III
Concerto per violino IV
Concerto per violino IX
Concerto per violino V
Concerto per violino VI
Concerto per violino VII
Concerto per violino VIII
Concerto per violino X

So the 9 is between 4 and 5...