First of all, I would like to commend this awesome plugin for it helps a lot of people and also a great help for my ongoing project.
I would like to suggest that there would be a subcategory for each list.
Lets put it into an outline,
we have here a main category and it is subdivided into several subcategories.
Example:
I.
A.
a.
i.
ii.
b.
i.
ii.
B.
a.
b.
https://wordpress.org/plugins/wordpress-form-manager/