3 level rowset peoplecode to generate a xml data file for BI report

Hi,

I am trying to create a XML publisher report to report for a batch which contains multiple invoices and each invoices with multiple lines

BATCH_REC - Level 0 ( Batch ID)

HDR_REC - Level 1 (Invoices)

LINE_REC - Level 2 ( Lines)

When the user print report by selecting print button on page, report should be generated 

for e.g : Batch has 5 Invoices , then the report should print 5 pages report should be printed with 1 invoice per page and associated lines.

 I am trying to use XML file data source .

Can someone help me creating a XML sample data file to create the template.