I thought of a way to do it, but unfortunately I'm not completely sure as to how to write it. I seem to get lost in my mind everytime I think I've got my thoughts arranged. But anyway. My idea consisted of two while/for loops and comparing the string part of the file (ie, w/o the numbers) against the file that was run through the loop(s) previously.

Example:
file1: clocks - category clocks
file2: clocksvert - category clocks (matches above file) subcategory vert (part of filename that doesn't match)

I hope this makes sense. Thanks once again.