You will need to resort to VBA to send to multiple email addresses.  Some of
the code you will need is in the article
"Mail Merge to E-mail with Attachments" at

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

and I based that on the second method in the article

"How to send an email from Word using VBA" at:

http://word.mvps.org/FAQs/InterDev/SendMail.htm

Yes, unless you follow the suggestions Doug has made or are
a. either able to design a query that returns one record for each distinct
e-mail address in each record and which can also be used as the data source
for a merge (and be aware that if you need to use a UNION query to do this,
the query may not be listed when you try to connect to it from Word
b. or able to modify the structure of your database to take account of this
requirement.

An example of the sort of UNION query (let's call it myquery) that could do
(a):

SELECT ID, manager_email AS 'email' FROM mytable WHERE manager_email IS NOT
NULL
UNION
SELECT ID, planner_email AS 'email' FROM mytable WHERE planner_email IS NOT
NULL

where ID consists of the primary key field(s) of mytable. (I may have got
some of the details wrong in here, e.g. used the wrong sort of quotes around
'email' etc).

To use this as part of a data source, you would need another query such as

Select  * FROM myquery, mytable WHERE myquery.ID = mytable.ID

(or use an INNER JOIN if you prefer)

But as I say, you might not be able to connect to this query, at least using
the default connection method (OLEDB).

Peter Jamieson