Okay, here's the solution.
In template/catalog/product/view> attributes.phtml use the following:
<?php
$_isLoggedIn = $this->helper('customer')->isLoggedIn();
if($_isLoggedIn == true){
$_myGroupId = Mage::getSingleton('customer/session')->getCustomerGroupId();
if($_myGroupId == 2){
echo '<td class="label">Attribute Name/Label</td>';
echo '<td class="label">';
if ($_product->getResource()->getAttribute('attribute_id')->getFrontend()->getValue($_product)):
echo $_product->getResource()->getAttribute('attribute_id')->getFrontend()->getValue($_product);
endif;
echo '</td>';
}
}
?>
Thanks to @nvoyageur for the initial pointer in the right direction!