Crosstab report add bunch of totals to end of report

[bioCam]

I have a crosstab report.  Column has Year.  Row row has Office -> Group.  Measure is a Percentage % where it is = (Qty sold for the Group for the Office for the Year) / (Qty sold for the Office for the Year). 

There are always 3 Groups for each Office (could be many Offices depending on what the user selects). 

I need to add Totals for the 3 Groups at the end of the report..

Total Group 1 = (Qty sold for Group 1 for all Offices for the Year /  Qty sold for all Offices for the Year  )
Total Group 2 = (Qty sold for Group 2 for all Offices  for the Year /  Qty sold for all Offices for the Year  )
Total Group 3 = (Qty sold for Group 3 for all Offices for the Year  /  Qty sold for all Offices for the Year  )


The result should look like this..  I don't know how to can add the totals to the end of the report.  Any advise please.

                                    2009       2010        2011
---------------------------------------------------------
Office AA    Group 1          9%        14%        23%
                 Group 2          ..   
                 Group 3          ..
Office BB    Group 1          9%        14%        23%
                 Group 2          ..   
                 Group 3          ..
---------------------------------------------------------

Total          Group 1          9%        14%        23%
                 Group 2          ..   
                 Group 3          ..
-----------------------------------------------------------

[Rahul Ganguli]

Create a dummy data Item containing value 'Total'. Insert this data item as peer of Office, then insert Group as child of Total.

Regards,
Rahul