Laravel PDF - collect multiple files into single PDF

I use in my project barryvdh laravel-dompdf package.
Users might generate a PDF with some personal information, till here everything is ok:

$pdf = PDF::loadView('personalInfo', $userData);
$pdfFileName = "personal-info-{$userData['username']}.pdf";
return $pdf->download($pdfFileName);

Admin should be able to download information of users, and in case of selecting several users, instead of generating several files I would like to collect all users PDFs into a single file.

How can I do it?

via Chebli Mohamed