Hi Michael Lorentz w/Cc Ivan54,
A hub site cannot be joined under another hub site.
I thought to take a moment and give perspective on the various levels and components Microsoft offers via SharePoint to help build out your full intranet. I do get the value of nesting a nested nest, and also beleive from an user perspective that there is not one site that ever rules them all - it's the site that is needed now, and even further it's the content in the site that may surface elsewhere at this right time in the right (often virtual) place.
With SharePoint hub sites we feel we're introducing an important mechanism to help organize and promote related ideas and people as one, at least until that one becomes three, or twenty, or several humdred - and then you have several hub sites - to the point of your question. And every company will have varying informational architecture needs - and these will change as the business changes.
Here's a quick glance at the various components we offer alongside hub sites - of which I feel the collective give you targeted outreach and collab, personalized aggreagation of sites/people/content and certainly scale felxibility to build what you need beyond out of the box:
- Communication sites
- Team sites
- The SharePoint home in Office 365
- SharePoint mobile apps
- Custom and partner solution sites
- Microsoft Graph (how we use it and the available API to build your own relevant, intelligent experiecnes right into your sites, into your intranet).
Thx,
Mark