UNIX for Advanced & Expert Users

I've figured out to do a mail merge with /usr/lib/sendmail which is extremely helpful as it is lightning fast compared to an Outlook mail merge which pretty much locks up my machine while it struggles to push out the emails. I figured out how to send html emails, with dynamic variables, and how our company translates id's to addresses which is 95% done. The last obstacle I'm facing is that the emails do not show to whom the email was sent.

When I use Outlook mail merge, which does not have an option for Cc'ing multiple users, I have to put this pathetic note at the top saying "This email was also sent to <person1>, <person2>, <person3> (Outlook mail merge does not allow cc)". So I'm trying to use sendmail but it's now showing the recipients in the received mail so it doesn't achieve the desired result. This is how I have it set up:

Code:

while read line
do
REQUEST_NUMBER=`echo $line | cut -d" " -f8`
USER_LOGIN=`echo $line | cut -d" " -f2`
END_USER=`echo $line | cut -d" " -f3`
REQUESTOR=`echo $line | cut -d" " -f4`
SERVER_OWNER=`echo $line | cut -d" " -f5`
(
cat html_greeting
echo $END_USER
cat html_body
echo $REQUESTOR
cat html_server_owner
echo $SERVER_OWNER
cat html_closing
) | /usr/lib/sendmail -f NO-REPLY@domain $SERVER_OWNER,$REQUESTOR,$END_USER

done < txt

Where txt is a sheet of data w/ all the id's and stuff on each line. I tried putting the recipients without commas, inside quotes, with commas and inside quotes...several different combinations. The emails are sent and received but the three people will not see that they have all been send the email so there could be some confusion as to who is in the loop and who isn't. Is there a reason those three addresses would not show on the receiving email?