so after browsing through many packages like TCPDF, FPDP, DOM2PDF and many other excellent php pdf packages, I couldn\'t find this feature in any packages where it allows to spl
PDFMerger has this functionality, and I personally enjoy its simplicity.
$pdf = new PDFMerger;
$pdf->addPDF('pdf1.pdf','20-100');
$pdf->addPDF('pdf2.pdf','30-50');
$pdf->merge(); // output PDF, you can specify additional parameters here