There are several fax "presentment targets" pre-defined. You could purchase a compatible fax server product, compile the forms including that target and then define the appropriate tasks for a print job to create the compatible output file into the fax server's input folder. For more information refer to the Print Agent Reference manual & look in the index for 'fax'.
Commercial fax server software can be quite expensive so the other choice would to be to create your own (this is what we will be doing). A fax card and associated software, including a programming API to the functions of the software is a good start. Additional software may be necessary to be able to convert file formats (PCL or PDF to TIFF, for example) may also be needed depending on the requirements of the fax software.
I would point you in the direction of ProTechnology Automation. They have a product called Output Director that can properly parse files, separate them and properly prepare them for whatever fax service you may be using. Check them out at http://www.protechinc.com
Give them a call and I'm sure they would be happy to discuss options.