user behavior – Global object to apply to each page – or – Custom object

I have a site that allows users to create and share lists. Each page represents a different list. I add a secondary list below that represents a shared or global list on all pages of the user. Although this secondary list is global, I want the user to be able to create a custom variant that is not global.

So I essentially manage a single global list that can be changed on any page, but you can turn off the overall look page by page.

How would you expose that?

Here's what I've

enter the description of the image here