How to Exclude Subchapters/categories from a Dropdown

Hello,
I’m currently working with Easel, and the plugin Comic Easel.
The category structure is broken down by chapters as seen here https://img.photobucket.com/albums/v242/C_San/chapters_zps16dc55e1.jpg
And I am using the Comic Easel- Chapters widget that looks like so https://img.photobucket.com/albums/v242/C_San/widget_zpsabbbd380.jpg (renamed Story Selector here).

My question: How can I, if possible, exclude sub-chapters of one chapter from the dropdown list (Chapters widget)? I will be adding many sub-chapters to the main “Misc Scenes,” and would like to be able to automatically hide all subchapters within on the dropdown list.
If I have to manually code out each subchapter, that’s fine, but I’d really prefer it to be automatic, as I will be moving some of those posts from out of that Chapter as they reach past a certain point.

Page in question: https://tobylotak.com/story/the-reunion-log3/