You will need some hand coding to accomplish this.
you need to loop through the cart contents to return the IDs of the items purchased, convert the list of ID's to a comma separated list. For example:
<?php
while (!$eCart1->EOF()) {
$cartItemsArr[] = $eCart1->DisplayInfo("ID");
$eCart1->MoveNext();
}
$eCart1->MoveFirst();
$cartItems = implode(", ", $cartItemsArr);
?>
then use $cartItems in a recordset to return the email addresses that relate to the Ids
for example:
SELECT * FROM table WHERE ID IN($cartItems)
you c an use that recordset in the receipt mail.
if you need help accomplishing this, we can help in a premiere support appointment.