I am looking for ideas for ready made sw / add-on (free or paid) or for ideas as how to create such a sw a solution to the problem described below.

The Problem:
I need to create multiple documents which have a common base.
However they have differences in many places. .
The document are “living document”, meaning there are changes to both common and non-common sections.
I do not wish to manage each document separately since changes to common parts would need to be done to each document.

My Vision
What I envision is a single Master document from which I will be able to create different Flavors. For example, to generate flavor #1 I shall use the Master document and view it in a filter showing common + #1 content and will then save it with only that content.
With this concept, differentiated parts will need some marking to allow identifying in which flavor they should be present.

Examples for Differences:
- text within paragraphs
- text within tables
- entire table line
- titles

Thanks ,