<?pdf
       include 'PDFMerger.php';
       $pdf = new PDFMerger;

       <!-- Merge 'common.pdf' and 'diff-1.pdf' -->
       $pdf->addPDF('commonpdf/common.pdf', 'all');
       $pdf->addPDF('allpdf/diff-1.pdf', 'all');
       $pdf->merge('file', 'pdftest/first.pdf');

       <!-- Merge 'common.pdf' and 'diff-2.pdf' -->
       $pdf->addPDF('commonpdf/common.pdf', 'all');
       $pdf->addPDF('allpdf/diff-2.pdf', 'all');
       $pdf->merge('file', 'pdftest/second.pdf');

   ?>