Don’t know if you’ve found a solution for this. If you’re going to try to eliminate duplicated then you’ll need to loop through your list before or after you sort it and take them out. As a simple example:
$already_shown = array();
foreach ($array as $value) {
// i'm using isset() because it's faster than in_array()
if (!isset($already_shown[$value'])) {
$already_shown[$value] = $value;
// code to show your value here
} // end if not already shown
} // end foreach
