oooooh, pmkprog, if it were only that simple. Merging your document with mailing data is the least of your worries.
The fiery will do it, and, so will a thousand other programs. You can even use the mail/merge function of Microsoft Word. Your biggest problem is that you will need to either purchase a Postal Presort program, or, outsource that function.
Effective Jan 2013 (just a few weeks from now), the only barcode permitted in order to receive a presort discount will be the new IMB (Intelligent Mail Barcode). Part of that barcode includes your USPS MID (Mailer Identification) number, so, in order to print the barcode in the first place, you need to fill out the forms and apply to the USPS to get your MID. Once obtained, your presort software (we use BCC MailManager from Bell & Howell), will generate the characters that will convert to the barcode. The presort software will append a field to your data that looks like a long string of "F",s "A"'s, "D"s, and "T"s. It will look something like this:
"TFFADFTTAAFDFTAFDDTDTDFATTTFATTTADTTFFATDDFFTDAAAATTTAAAAADTAFAFA"
You can download the actual IMB Font free from the USPS's web site to convert it to the barcode, but, the ones you buy from a 3rd party will work better.
If you are new to the mailing biz, let me caution you that just being able to print mailing information and barcodes on your mail piece doesn't necessarily mean that you can receive a presort discount. There are a myriad of rules and regulations ranging from the physical dimensions of your mail piece to how it is prepared and trayed that you will need to be familiar with.