You can use Word's Catalogue/Directory Mailmerge facility for this (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/showthread.php/154370-Microsoft-Word-Catalogue-Directory-Mailmerge-Tutorial
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 and includes working field codes for the various examples, plus macros where applicable. Do read the tutorial before trying to use the mailmerge document included with it.

For some worked examples, see the attachments to the posts at:
https://www.msofficeforums.com/mail-merge/9180-mail-merge-duplicate-names-but-different-dollar.html#post23345
https://www.msofficeforums.com/mail-merge/11436-access-word-creating-list-multiple-records.html#post30327
http://windowssecrets.com/forums/showthread.php/157725-Word-2010-Merge-from-excel-into-Table-Directory?p=928391&viewfull=1#post928391

Alternatively, you may want to try one of the Many-to-One Mail Merge add-ins, from:
Graham Mayor at http://www.gmayor.com/ManyToOne.htm; or
Doug Robbins at http://bit.ly/1hduSCB

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]