Custom browse / sort tag

I’m using custom scan and custom browse to be able to browse my jazz and classical library. For example, for classical albums I tag work, opus, movement, period, perfomer, band, etc.
Now comes the tricky bit; when browsing by period (baroque, renaissance, classical, romantic, etc), I would like to sort the period chronologically. For example, the menu would look like (from top to bottem)

Medieval
Renaissance
Baroque
Classical
Romantic
Modernist
Postmodernist

Is there a way to configure the custom sort or is it not possible? I think I have the options to sort numeric or alphabatically but that does not help in this case.