Try this:
Step 1.
Create the Pivot Table and place in RowLabels "Group" and under it "Level". Now, place "Level" as count in "Values" field.
Step 2.
See the picture below. Click in the black arrow in the right side of "Level" (you can't see it in the picture but it is supposed to be inside the red circle). Choose "Values Filters", then "Top 10" and then set the number to 1 (top 1). Done!!
Attention: you need to do step 2 for "Level". If you do the same to "Group" it will not work.
Edit: this is the result and how the Pivot Table should look like.
Now to shape the output to the desired format:
- Under PivotTable tools > Design, set the Report Layout to Tabular form
- Disable totals and subtotals
Assuming default settings you can now easily copy the list of Groups and LevelModes