Consider making your "Lists" a database. Think of each list as a category as you have already stated. You would need a column for "category" and/or each "subcategory". Consider the image here. I am a movie buff and created this database for my movies that can be categorized by Genre, and sub-genre, and further by runtime, leading actor, or even actor mentioned in the movie, and release date. Click on the image for a "zoomed view".
The top is an image of my working database in "Design View". This is a database set up in MS Access. The image below the database is my "Table". Your lists are actually tables. A table is nothing less than a list. Take a closer look at the columns in my "table". With these headings I can manipulate my Titles and a dynamic way and sort them any way I wish. Although this is more than what you are doing with your Excel datasheet lists, I hope this will inspire you to think in terms of data and tables, instead of lists.