I'm looking into merging multiple attachments (.pdfs) into a single attachment.
The research I have done so far suggests that there is no native way to achieve this in Apex.
The only feasible way seems is to either leverage an App, such as CongaComposer or DocuSign (paid for) or, as per this link, to make a webservice to the Google App Engine.
Has anyone been successful in merging attachments together in Salesforce without the assistance of a paid-for App?