If you want to send a standard message to a group of people, yet have the message custom written to every person in the group as if they were the only recipient, you can use The Bat!'s mass-mailing features.
Create a Quick Template containing the text of the message and use template macros to create personalised inserts for the message (like first names in greetings, etc.). In the Quick Template editor, tick the "Use for new messages / Mass mailing" box.
In the address book, create a group for the intended recipients for this mass mailing (if you don't already have one).
Once you have at least one mass-mailing quick template defined, the Address Book contains a couple of new menu entries: New message using template and Mass mailing using template. Each of these menu options leads to a list of available mass-mailing quick templates.
First select your recipient group. Then select the option you want (New message or Mass mailing) and that's it - all done!