Hey @Paul_Danyliuk 
hope all good?
I am not sure if my problem is solved already with this post, what I am trying to do is to propagate a new table with 2 columns; one with one value and the other with 1-n values
Finally I want to have this result (for each region and category one row)
This formula is not working:
r_region.FormulaMap(AddOrModifyRows(r_category,Region=Region and Category=CurrentValue.Category,Region=Region,Category=CurrentValue.Category))
Any suggestions?
Thomas