I have report in Excel format (Excel 2007) from Accountant department - and it has Groupping by Rows.

+ Client 1   300$  (group Bills by Client)
|-- BIll 1   100$
|-- Bill 2   200$

So in Excel It looks like this in plain rows format (If I ungroup those rows):

1 Client1 300$
2 Bill1  100$
3 Bill2  200$

1,2,3 - row numbers.

So I cant Pivot these data to get Client-by-Bill-SUm report, because rows with Client Name are not Connected (that is necessary for Pivoting info by Client, Bills) with Bills rows after UnGroupping.