Mail to php form with multiple adresses

I seem to be running into a small problem. I need to have my flash form mail to multiple addresses. The form works fine when there isn’t a secondary address. But for some reason, testing it with the second address it won’t send another email or copy of the email to the other addressee. Below is a copy of my php mail to form.

//Destination Email ID
$to = "[email protected],[email protected]";
//Name of the Person
$namenew = $_GET['name']; 
//Email Id of the person
$emailnew = $_GET['email'];   
//Phone Id of the person
$phonenew = $_GET['phone'];   
//Feedback detail
$feedbacknew = $_GET['feedback']; 
//Subject line of the email
$subject = "Feedback Form"." "."$emailnew";  
/*********** Email body *******************/
$matter = "Below are the details filled by"." "."$namenew"."

   "Name:"." "."$namenew"."

   "Email:"." "."$emailnew"."

   "Phone:"." "."$phonenew"."

   "Suggestion:"." "."$feedbacknew"."

mail("$to", "$subject","$matter","From: $emailnew");

My searches yielded some answers but test results seem to come up short. Any help in making this work properly is much appreciated, Thanks.