You would have to use a macro to do this.  The one in the article "Mail
Merge to E-mail with Attachments" at

http://word.mvps.org/FAQs/MailMerge/MergeWithAttachments.htm

would be a good starting point.  You would need to do something similar as
far a creating a catalog type mailmerge document is concerned and then
iterate through that, picking up the email addresses from each row in the
catalog and using them with each document=section of the document that you
want to email.