How to reuse JasperReports queried data

Need to reuse the already loaded fields in the report. How can I do this.

1. Main query loads 20 records It's grouped by field1 and then by field2
2. Display(print) all grouped records in the report
3. Up to this is OK.

Here's the Problem area,

1. In the summery band I need to give a summery of field1 group and field2 group seperately
2. To do this i intend to use two datasets with tables in the summery band to display field1 and field2 group summaries.
3. I need to do this without using the same query on both the datasets copied from main report just to reprint group summary.

How can I achieve this?