Hehe, I am not yet as deep in the PDF 
Maybe then add a short reference to page 130 on page 8?
I did this and … it is fantastic!
The more I think about this, the more this is exactly the feature that I was looking for in https://discourse.devontechnologies.com/t/accessing-dt-content-as-volume-in-finder
It mimics the behavior of DTTG where other Apps can access the group hierarchie within DEVONthink.
This would be a reason to go back to what I was doing before - I had all content in the global inbox.
I just now moved everything from the global inbox to 3 different databases 
I think about reversing this again to have full access from the Finder.