How to suppress zero values for summary in Cross Tab

Hi

I have a cross tab with Country as Column, Region as Row and Last year Sales as summary field.

The cross tab is displaying all zeros for those regions, which are not part of the country.

For example for Country Argentina, Region Abu Dhabi is displaying $0.00 (sum of last year sales) as it is not a region belonging to Argentina.

Any suggestions would be appreciated.

Thanks in advance.

Regards

Sourashree