PHP - Magento mail function how to set multiple recipient mail id based on if condition?

Following code for sending multiple recipient mail based on the first digit of sku from order received,

<?php
class Gta_MerchantNotification_Model_Observer {
  public function merchantremainder($Observer) {

$order = $Observer->getEvent()->getOrder();
$order_details = $order->getAllVisibleItems();

$itemData = array();

foreach ($order_details as $list) {
  $incrementid = $order->getIncrementId();
  $sku = $list->getsku();
  $name = $list->getName();
  $price = $list->getPrice();
  $Qty = $list->getQtyOrdered();

  $this->sendMailbasedOnSku($sku);

  $message = 
    "<tr>
      <!-- <td>$incrementid</td> -->
      <td>$sku</td>
      <td>$name</td>
      <td>$price</td>
      <td>$Qty</td>
    </tr>";

  $itemData[$list->getId()] = $message;

}

$finalMessage = 
  "<p>Order Id : $incrementid</p>
    <table border='1'>
    <tr>
      <!-- <th>Id</th> -->
      <th>Sku</th>
      <th>Product name</th>
      <th>Price</th>
      <th>Qty Ordered</th>
    </tr>";

if (!empty($itemData)) {
  foreach ($itemData as $data) {
    $finalMessage .= $data;
  }

  $finalMessage .= "</table>";

  $this->sendMail($finalMessage);

}

  }

  public function sendMail($message) {

$body = "$message";
$emailTemplate = Mage::getModel('core/email');
$emailTemplate->setFromName('Test mail');
$emailTemplate->setBody($body);
$emailTemplate->setSubject("Custom Email from observer");
$emailTemplate->setType('html');
// $emailTemplate->setToEmail('abc@gmail.com');

if($sku == '2')
{
  $emailTemplate->setToEmail('abc@gmail.com');

}

elseif($sku == '3')
{
  $emailTemplate->setToEmail('xyz@gmail.com');  

}

elseif($sku == '4')
{
  $emailTemplate->setToEmail('qwe@gmail.com');   
}

else
{
  $emailTemplate->setToEmail('ewq@gmail.com');
}

$emailTemplate->send();
  }


  public function sendMailbasedOnSku($sku)
  {

// Mage::log('Line no: 94 '. $sku,null,'test_sku.log',true);

$chk_sku=(int)substr($sku, 0, 1);

$emailTemplate = Mage::getModel('core/email');

if($chk_sku == '2')
{
  $emailTemplate->setToEmail('abc@gmail.com');
}

elseif($chk_sku == '3')
{
  $emailTemplate->setToEmail('xyz@gmail.com');    
}

elseif($chk_sku == '4')
{
  $emailTemplate->setToEmail('qwe@gmail.com');    
}

else{
  $emailTemplate->setToEmail('ewq@gmail.com');
}
  return $emailTemplate->send();

  }
}

Now 95% working exactly, if order placed with two products with sku combination like 2 & 3, Now mail received by exact both mail - abc@gmail.com (sku start with - 2) & xyz@gmail.com (sku start with - 3) but empty message, and also last mail id in if condition received with data.