How to add custom Post access/visibility levels

Hey guys,

I’m familiar with building nodejs apps, and I want to create additional Post access levels for my blog’s readers. The use case is simply that I need visibility categories aside from the default [‘public’, ‘members’, ‘paid’] once posts are created. Can someone provide guidance on which parts of the API I need to update in addition to the schema and Post resource if any?

I’m asking for API related assistance because from what I can gather so far, this isn’t an available feature out of the box. Although I could be missing something here.

Ghost version - 3.1.1