I've read the thread. Thank you.
Given that the problem involved one parent table and one child table, I don't understand the need for a third table, "grandchildren" or the content of this table. I also didn't see any mention of "grandchildren" in the original post.
In my case, The "parent" is Surveys and the "child" is Notes.
Do I need a third table to display two portal views of the Notes table? One portal listing all Notes and another showing just one field from the selected row in the first table?
You've indicated that you want two portals on your layout. That implies a relationship between three table occurrences: 1 for the layout and 1 for each portal.
The layout's table occurrence is the Parent
The first portal, the "master" portal refers to Child
The "detail" or second portal shows related grandchildren.
And please visit the link provided where I explain the notation that I used in much more detail with pictures to show how what I typed as text translates into table occurrences in the relationship graph.