Can I generate composite foreign keys using a dataset based on the row?

I need to combine column values in the same row together and add them in another schema. I uploaded the data as a dataset; now I need to concatenate the column values and add them based on the current row in the current schema.

Is there some way I can reference a dataset this way?

I tried using Formula and Dataset columns and the from_dataset function, but I don’t have a singular ID column I can use as a join_criteria. I need to specifically generate values by row number. Can I do this

I see this is from over a year ago, with no answer. I too would like to know about being able to use/set composite keys