Abstract document content or referenced content.

So we have content that we’d like to use in multiple documents (mostly text) that is constant and other areas of the document are unique to the document. This can’t be concisely delineated into full pages either. This isn’t tiny content that is suited to variables either. This multiple pages of copy, tables etc that flows from page to page.

I can’t for the life of me figure out a way to abstract out content into a single source so changes to that content only need to be made one single time and all documents that reference that content are updated automatically.

I can’t be the first person to want to solve this.