Saving Multiple Versions of the Same Document

I'm working on a document that will be distributed in multiple countries. Because of different regulatory requirements in each country, each version of the document has slight variations. I am saving each version of the document as a separate file in a separate folder, however, when I make a change to one document it gets saved in all documents, even though I only have one document open, each document is saved in it's own file, and each document has a different document name. 

I have tried saving each document in its own folder under a parent folder, and also in its own folder on my desktop. This does not seem to change anything. I've also tried creating a new book and importing files from another version, then saving, and that doesn't fix the problem either.

How do I stop this from happening?! Right now I have 3 documents, but soon it will be in the double digits, and I cannot change each file with every change every time I need to update.

Thank you!