I presume that no responses may mean that what I'm looking to accomplish is just not possible? I guess I will have to look into using filtered portals instead.
It can be done with relationships, but not via your case calculations.
When you refer to a field from a related table in a calculation, it only refers to data from the "first" related record. If there is more than one related record, data from the other records might as well not exist.
To access data from a different record, you either need a relationship that matches to that record as the first or only related record, a SQL query in the ExecuteSQL function call or, as you have mentioned, by using a filtered portal.
Thanks Phil. I had found a response you made in another post about using a relationship to show the desired records. That's what I ended up doing. I created a new calculation field where the result was "1." and then created a new TO that had 'SortID' = 'that calc field' as an additional relationship to the primary key = foreign key. I was then able to show the CategoryGrade field from that TO and it showed the field data of a specific related record in a parent field. It worked just fine. Thanks Phil.