How to have chart showing data for "current group"

Hi there,

I am working with a dataset with three columns (city, country, population) that maps cityname to the country where the city is and the city's population. I would like one pie-chart for the citys from one country (for each county). So i have inserted a group into the report structure (grouped by country) and i have added a pagebreak-before to the group header and a string-field that names the "current" country. I have also added string-/number-field for city-name and population to the details band and a pie chart to the group footer. The preview now shows me lots of single pages each page showing one data-row for the details-band and one pie-chart. The problem is that for example for india the dataset has 81 entries but the corresponding page in the report shows only one entry.
I hope this description is possible to understand?
I would like to know how i can establish the expected result that i have one (or more) page for each country with all the data for this country or what i am doing wrong so that this result i could not establish.

sincerely

matthias