Using Formmail.php and trying to select multiple recipients

Hi! Total "newbie to programming" here.

I'm using Jack's Formmail.php, code at:
http://www.dtheatre.com/scripts/sour.../formmail.phps

and I'm trying to figure out how I can have it send an identical message to
more than one recipient, based on a checkbox selected by the user who
submits the form.


<input type="checkbox" name="email1" value="recipient1" />Recipient 1
<input type="checkbox" name="email2" value="recipient2" />Recipient 2
<input type="checkbox" name="email3" value="recipient3" />Recipient 3

where "recipient[n]" is stored in the script:

"recipient1" = "email1@email.com"
"recipient2" = "email2@email.com"
"recipient3" = "email3@email.com"

If the user checks recipient1 AND recipient3, it would send the message to
both of the above e-mail addresses.

Is there a script out there that could do this better?
Any help you can give me would be very helpful!

Thanks so much,
Maggie