Hello Cecilio,
The subreport is used for it.
The examples are located at this page:
http://valentina-db.com/docs/dokuwiki/v7/doku.php?id=valentina:vcomponents:vreport:demos:sakila
Uncompress two archives into a single directory, so the datasource DB will be found automatically.
The subreport example is "Report_PaymentsOfCustomers".
The main report shows the information about the customers.
The subreport prints all payments made by each customer.