Appending pre-existing .docx to a Pilot generated .docx

I have developed a pilot web port application which allows users, via an html input form, to generate a word document output and am trying to append other pre-existing word documents to this based on the inputs provided - however this is proving somewhat difficult as I cannot for the life of me figure out how to get Pilot to come even close to doing this.

Essentially in the input form the user will select an activity which they are going to perform, each activity has a pre-defined SOP document and a pre-defined Safety document associated - I'd like these to simply paste in at the end of my pilot generated Word document so that the user has all documentation in one place and does not have to link out to get to the SOP or safety documents.

Thanks