Exclude Group and sub groups from printing

[czupet]

I am using iReports 5.1:

 

In CrystalReports you can add a filter to exclude records by Sum like this:

Sum ({Amount}, {ZipCode}) > 0.00

 

How can I accomplish the same in Jasper Reports?

For example if I have a Zip code

and I do a sum by Last Name in the Zip code group and I only want to display Zip Codes that have sum > 0

for example

ZipCode: 12345

Family1 Sum 10

Family2 Sum 0

Family 3 Sum 100

(I want to display all of them)

ZipCode: 98765

Family1 Sum 0

 

I don't want to display this Zip Code or anything under the Zip Code.

 

Thank You 

 

Peter