Sub-report on ireport

I'm trying to make a report where each code has x clients. Example

Code 1:

Bruno
Rodrigo
Fernando

Code 2:

Rafael
João

I retrieve these codes from a database, for example:

1 Bruno
1 Rodrigo
1 Fernando
2 Rafael
2 João

As you can see, the codes repeat themselves, so when I generate my report that contains a sub report this whole amount is repeated and the report gets huge.

In short, how could you leave this report as the first example presented?

public void gerarRelatorio(List<PreEmissao> lista, String contrato) throws JRException {
        Map<String, Object> parametros = new HashMap<String, Object>();
        /**Parametros, essa lista é o DataSource do sub relatório*/
        parametros.put("SUBREPORT_DIR", "src/main/resources/Report/Faturamento_subreport.jasper");
        parametros.put("lista", lista);

        JasperReport jasperReport = JasperCompileManager
                .compileReport(getClass().getClassLoader().getResourceAsStream("Report/Faturamento.jrxml"));

        /**Essa lista que é passada carrega o DataSorce do relatório principal, dela eu só pego o código*/
        JasperPrint print = JasperFillManager.fillReport(jasperReport, parametros,
                new JRBeanCollectionDataSource(lista));

        JasperExportManager.exportReportToPdfFile(print, "D:/Ouvidoria/Relatorio" + contrato + ".pdf");

        System.out.println("Relatório gerado.");

    }