Hide page in nav, but render specific nav when page is open

[jpluscplusm]

I'm in a similar position to the user who asked "Can pages be hidden from navigation?" in #5856. In that discussion, the user asks how to omit a page from the nav, as their docs site has a large number of pages that make a fully populate nav unwieldy.

I have the same need, but with an additional wrinkle: when such a page (unmentioned in the nav) is open, I'm trying to work out how to render the page's nav as if it were mentioned at a specific location.

As an example, imagine a site with a top-level hierarchy like this:

  > Home
  > About
  v Docs
    > Introduction
    > Guides
    > References

When the Guides section is selected, the navigation.indexes feature jumps to the section index doc, and the nav becomes this:

  > Home
  > About
  v Docs
    > Introduction
    v Guides
+     > About these guide
+     > Popular guides
    > References

The above is all possible (and working!) with Material for MkDocs 😄

Here's what I'm trying to achieve: when an individual guide is being viewed I'd like the nav to act as if the page were inside the Guides section, instead of just displaying the top-level nav view. In other words, to display the same nav AS IF the Guides section index were being viewed.

I've been unable to configure this in vanilla, plugin-less Material for MkDocs.

I'm currently trying to configure mkdocs-awesome-nav to achieve this, but its page hiding feature seems to place an "ignored" page (i.e. the individual guide, above) in the same limbo state as the vanilla setup - where only the top-level, default nav is displayed.

Has anyone needed this and figured out a solution?

Does anyone else have any ideas that might help?