Word can only use a single flat file as a data source, so as a minimum, you
will have to combine the two files.  You will then however end up with a
file in which the producers are each repeated for each product that they
produce and that then puts you in the trying to perform a "multiple items
per condition (=key field)" mailmerge situation which Word does not really
have the ability to do.

If you have Access, it would be easier to do it all in Access, using a query
that linked the producers from one table to their products in anothter table
and then use a report to generate the letters.

Alternatively, see the "Group Multiple items for a single condition" item on
fellow MVP Cindy Meister's website at

http://homepage.swissonline.ch/cindymeister/mergfaq1.htm#DBPic

Or take a look at the following Knowledge Base Article

http://support.microsoft.com/default.aspx?scid=kb;en-us;211303

or at:

http://cornell.veplan.net/article.aspx?&a=3815

When merging can the date in the merged document be saved at the time of the
merge whilst still updating the date of the original document. For example
when preparing a customer quotation and saving the merged document it
preserves the saved date but updates the original document ready for the next
merge. I have tried Createdate and savedate but neither seem to work.