Hi Mitch,
Presumably, you're storing all the client data in a database or, perhaps, an Excel workbook. In that case, you could use Word's Catalogue/Directory Mailmerge facility for the letter generation (the terminology depends on the Word version). To see how to do so with any mailmerge data source supported by Word, check out my Microsoft Word Catalogue/Directory Mailmerge Tutorial at:
http://windowssecrets.com/forums/sho...ngs-(2000-2010)
or
http://www.gmayor.com/Zips/Catalogue%20Mailmerge.zip
The tutorial covers everything from list creation to the insertion & calculation of values in multi-record tables in letters. Do read the tutorial before trying to use the mailmerge document included with it. You could enhance the tutorial's examples with ASK/FILLIN fields that provide prompts for anything additional that is to be input at the time, including the triggering of the inclusion of additional boilerplate text.
For a recent, worked example, see the attachment to post #13 at:
https://www.msofficeforums.com/mail-merge/9180-mail-merge-duplicate-names-but-different-dollar.html
Alternatively, you may want to try the Many to One utility on the MergeTools Add-in that you can download from the following page of Doug Robbins' Windows Live SkyDrive:
https://skydrive.live.com/?cid=5aedcb43615e886b#cid=5AEDCB43615E886B&id=5AED CB43615E886B%21111
Be warned: unlike an ordinary mailmerge, none of this is simple where the potential exists for each client to have multiple records that have to be incorpprated into the same letter.