SSRS: Group by Item inside the details row, not as a separate column

I want to create a report which will "Group By" by specific element - For example: Ethnicity. After adding Group By in SSRS report, it adds a column. What I want is add the Group by element name here Ethnicity as a row as following

1. Select the Details Row Group, Drop down arrow click-->Add Group-->Parent Group-->Select Ethnicity in the Group by option.
   
2. Now select the Ethnicity group by cell in the Tablix-->Right click-->Insert Row-->Insert Group-Above. 
   
3. Now you can merge the cells of the new row
4. You can repeat the new Group by Row on every page
1. From the Column Group-->Select Advanced mode
2. Now from the Row Group-->Keep selecting the static until you find it select the new Ethnicity Row.
   
   Then from the Properties window set
1. KeepWithGroup: After
2. RepeatOnNewPage: True