Hi

Don't know how to do that in Word as I use word as a formatter/TOC creator rather than a true WP. But I do what you seem to want to do in software called Scrivener which is a document project manager. Primarily for book writing/manuscript creation/ V large report writing. IF you like - it is a very advanced Word Navigator function.

I use this software for report writing and writing textbooks. For instance if I use a section repeatedly but need to "fill in the blanks" I just drag over the relevent folder/page from the template. The software is NOT a WP but has most of the functionality of a WP (Fonts, paragraphing formatting) but will not do things like indexing/TOC/Captions etc. But you can just export it to Word once you're done for formatting.

Think of it as though you were writing a textbook and Scrivener will organise the book for you and Word will format it. It costs but is cheap around $40