$role = array_shift($roles); // First one
$fullname = fullname($teacher, has_capability('moodle/site:viewfullnames', $context));
$namesarray[] = format_string($role->name).': <a href="'.$CFG->wwwroot.'/user/view.php?id='. teacher->id.'&course='.SITEID.'">'.$fullname.'</a>';
Put an "if" statement around these lines like this:
$role = array_shift($roles); // First one
if ($role->roleid > 2){
$fullname = fullname($teacher, has_capability('moodle/site:viewfullnames', $context));
$namesarray[] = format_string($role->name).': <a href="'.$CFG->wwwroot.'/user/view.php?id='.
$teacher->id.'&course='.SITEID.'">'.$fullname.'</a>';
}$namesarray[] = format_string($role->name).': <a href="'.$CFG->wwwroot.'/user/view.php?id='.
$teacher->id.'&course='.SITEID.'">'.$fullname.'</a>';