Adding a rankings - set column - relations

I want to set a column based on a position entered against the items on the list in the app. The complication is that I’ve used a Relation between sheets and the positions are in the sub-relation.

The first sheet is Day>Ring>Class
The second sheet is Class>Competitor Number>Competitor Name> Position (I want to update the positions of the list of competitors - scoring them)

It’s sometimes hundreds of classes and the number of competitors varies per class.

Any suggestions on how this can be done?

Thank you

I’m trying to do the same thing. I’ll keep you posted if I get any traction on this