Numbering and sorting

Numbering my discs - I renumbered my whole collection, as the original numbers were by categories which I changed later. I sort my classical disks by composer, and the other categories by artist. Now the numbering lets me do only the entire collection. The different categories aren't very big, but the 100+ classical discs are numbered by some sorting which I can't figure out, it's by none of the columns I see. Could it be by the order of scanning?

My whole purpose of the OCD is to know what I have and where to find it, and I planned to number the discs in some orderly system, and re-arrange my shelves. (brrrrr)

I want to print one list of my classical collection - no problem. And another list of all other categories, sorted but together. The two lists will have a different sorting, so I think the simplest way to make the "all others" list is to sort by artist, sort by category, print the whole thing, throw away the classical part which won't have the right sorting. I don't know if I can select several but not all categories.