I have been able to get some level of function by moving pages (which brings their subpages along) from viewable documentation into a DEV not viewable (unpublished) documentation. It is a little unpredictable whether that DEV directory will show up in the public-facing docs, but it is straightforward to unpublish the content itself… just the documentation name presents unpredictably.
I’m interested to see what features the DeveloperHub team comes up with to make this work. I’m sure it will be better than what I’m doing!