I may be wrong, but I do not think the AssociatedDomains in that article are the ones I need. What I need is for Universal Links and circumventing the Apple Content Delivery Network. The article seems to be about VPN and similar network settings.
We have talked to a large MDM vendor, and they did not know how to do it. The mentioned article did not help them and they supported my doubts that it may not be the same topic.