Global object to apply to every page -or- Custom object

I have a site that allows users to create and share lists. Each page represents a different list. I'm adding a secondary list below which represents a shared or global list across all the user's pages. While this secondary list is global I want the user to have the ability to create a custom variant that is not global.

So essentially I'm maintaining a single global list which can be edited on any page, but you can disable the global aspect on a page-by-page basis.

How would you lay this out?

Here's what I've got: