Thank you all for replying.
I want to use the item group to categorize more general things such as: rings, earrings, gems, necklaces, etc...
I don't think the item group should contain hundreds of records.
If I create a DDL as a UDF, I will not be able to use the sales analysis, but how complicated would it be to create a query for that? it should calculate A/R invoice + A/R credit and group it by the UDF so I can see which product is top seller (regardless to the sizes)
What do you think about this solution?
Thanks a lot!