As I say, the only way is to format the unwanted paragraphs as hidden. Which
you could certainly do through code. You need some way to tag the paragraphs
you do/don't wan't to show. Easiest is to use a distinct style. Then write a
macro that sets that style's hidden property TRUE/FALSE.

But I suggest this is not a good way to approach the problem. The support
issues with documents that behave in unusual ways usually outweigh the
convenience that the method is supposed to provide. Some Word users panic if
a document is anything other than bog-standard vanilla Word -- they'll ring
you for help and blame you for *everything* that goes wrong on their system
ever more ("ever since you installed that template, my Excel doesn't print
properly ..")

My own approach is to write the documents with the additional detail on
separate, drill-down pages.