Query regarding to MS reporting services (Grand total problem)

Hi,

I have a problem reagarding Grand Total in the table footer.

I am showing only top 10 seeling for each department in report but i want sum of whole table seelings in table footer. not only 10 sellings which are shown in report. I want the sum of all 40 thousand rows.

  How i can do it.

If any one have idea about this please help me.

Thanks in advance.

 

Regards

Dinesh Tiwari