Generate several sheet with one template

[flefloch-payps]

Hello,

I have actually a template which I use to generate invoices like this :

 public function registerEvents(): array
    {
      return [
         BeforeExport::class => function(BeforeExport $event){
            $excelFile = $event->writer->reopen(new LocalTemporaryFile(storage_path('app/contracts/template.xls')),Excel::XLS);

            //// Invoice Sheet
            $invoiceSheet = $event->writer->getSheetByIndex(0);
            
            $spreadsheet = $invoiceSheet->getDelegate();
            $spreadsheet->setShowGridLines(false);

            // Invoice Number and Date
            $invoiceSheet->setCellValue("L3", $this->invoiceDetails["invoiceNumber"]);
            $invoiceSheet->setCellValue("I5", $this->invoiceDetails["invoiceDate"]);
........
return $excelFile;
         }
      ];
}

This single export is working fine, I update my template with my dynamic data and I finally generate the file.
But now I would like to generate 2 invoices with the same template with 2 different set of dynamic values.
If I simply add a loop in my registerEvent function I will only receive the last set since it will overwrite the previous set of data.
How can I acheive that ? I could generate 2 different files, reopen them and merge them into a single file that my endpoint could return but that seems a bit uneffective.
Is it possible, during the generation process to duplicate my template everytime need it and then generate my file in a single call?

Thank you.