No need for this feature, the solution is available. It would be nice to have more “Howtos” and more examples for the query editor. 
The solution is based on this post.
DALE: The "Doctor And Location Example" With Solutions For Queries, Relations & Other Stuff.
Show brand page on product page.
Relational field:
Assigning values in product page:
Query settings:
It doesn’t work if “Post type” is not set !!!
