Add a sub-report (using invoice detail table) to invoice group footer 2, then embed the file reference of the certificate in JPG format within the sub-report. Link via invoice number and group the sub-report on invoice number/Item number, and embed the JPG at item number footer, with a page break after the footer. That'll print a cert for every item on the invoice that has one. You may have to conditionally suppress items without certs, as well as invoice headers/footers (if you don't need them)... but it works. I think embedding the image will only work with Crystal XI though.