It is done by using Mailmerge Events.
See the add-in that you can download from fellow MVP Graham Mayor's website
at:
http://www.gmayor.com/individual_merge_letters.htm
It maybe simpler however to use a macro to execute the merge and then do
what you want with the document created by merging to a new document.

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Hope this helps.
Please reply to the newsgroup unless you wish to avail yourself of my
services on a paid consulting basis.
Doug Robbins - Word MVP
> Is it possible to run a macro automatically upon the completion of a
> merge?
> If so, how? Thanks.