In app/code/core/Mage/Sales/etc/system.xml in node sales_email -> order -> fields add something like this:
<copy_to2 translate="label comment">
<label>Send Order Email #2 To</label>
<frontend_type>text</frontend_type>
<sort_order>6</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
<comment>Comma-separated.</comment>
</copy_to2>
<template2 translate="label">
<label>Send Order Email #2 email template</label>
<frontend_type>select</frontend_type>
<source_model>adminhtml/system_config_source_email_template</source_model>
<sort_order>7</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</template2>
and in app/code/core/Mage/Sales/Model/Order.php -> public function sendNewOrderEmail() below $mailer->send(); add:
$copyTo2 = $this->_getEmails('sales_email/order/copy_to2');
if ($copyTo2) {
foreach ($copyTo2 as $email) {
$emailInfo2 = Mage::getModel('core/email_info');
$emailInfo2->addTo($email);
$mailer2->addEmailInfo($emailInfo2);
}
$mailer2->setSender(Mage::getStoreConfig(self::XML_PATH_EMAIL_IDENTITY, $storeId));
$mailer2->setStoreId($storeId);
$mailer2->setTemplateId(Mage::getStoreConfig('sales_email/order/template2', $storeId));
$mailer2->setTemplateParams(array(
'order' => $this,
'billing' => $this->getBillingAddress(),
'payment_html' => $paymentBlockHtml
)
);
$mailer2->send();
}