You could use a foreach loop and send multiple emails, or you could simply place each person's email from the array and append it to a Cc header:
foreach ($arrayOfPeoplesEmails as $IndividualEmail)
{
$whoToSendTo .= $IndividualEmail;
}
$headers .= "Cc: ".$whoToSendTo."\r\n";
The only thing I'm not positive on is the format of the list of email addresses. I've never used the Cc header, but I would try first seperating each email with a comma, and if that doesn't work try seperating with a space.
