When presenting a technical derivation within a Section of a Mathematica notbook, I often encounter the situation where a lot of "detail" separates equations (x) and (x+1), and I suspect many readers would prefer not to see this detail. I could use a collapsible subsection to hold the required material, but at the end of the subsection I would have to create a new Section to continue the main flow of the document. I find this to be stylistically awkward.
Have any of the wizards solved this sort of problem? Perhaps by developing a Style for a special section that can be collapsed or expanded in a standalone manner that doesn't interrupt the flow of the main document?