We use Anchor Tags (links to specific places within the same document) with a navigation section at the top and a "Back to Top" and links to "Related Sections" at the bottom of each section.
You need to do this in HTML mode, and we usually don't leave this up to our users, unless they are under 30. If they have the document it is usually easier and faster for one of us to add the anchors for them.
Also, during document development, we have often found that everyone is better off if they start off as separate documents, since different sections often have different editors - with a separate nav document that @ mentions the other separate sections. Once everyone has edited their piece and the approvers have wandered around in the "Collective" document via the nav document - then you can bring them all together in one document and add the Anchors.
This is also why we created a "Compound Document" ManagedSnippet (Managed Snippets Plugin - thank you Ryan Rutan) that displays just the actual text in multiple documents in a single Compound Document in a specific order. Editors and senior leaders can comment on the overall document and individuals can still just edit "their" section.
Hope that helps.
We also use Anchor tags on some of our documents and it has worked well. Someone on our side reported they don't work when you click the "View as PDF" link. Can you verify that, and list what version of Jive you are on?
The Compound Document sounds very interesting and we may have a use for something like that too. Can you provide a link to one that I could see? We also used Ryan's Managed Snippets Plugin for something else, but dropped it as some new widgets included in Jive 7 fit the bill. To my knowledge the Managed Snippets Plugin will not work with Jive 7.
As it is effectively an internal community, I can't share a link unfortunately.
I may just post a screen shot or video here.
We are currently on 6, moving to 7 in September. There are some options on Jive 7. DM me and I can see what I can do on both fronts.