Change grouping in a list report with crosstabs

[EarthDog]

I have a report that is a list and in every list cell i have 2 crosstabs that have master-detail relationship defined.



List query has 4 records.

I created a new data item in list query that returns 3 distinct values from the 4 rows of the query.

I need to replace the grouping in list, but i cant make the list return 3 rows.

How can i say to the list to group in the calculated data item (UNIT1) instead of (UNIT)?

I changed the grouping properties and the master detail relationships but i cant make it happen