Takes a string of resource ids and filters out the unpublished resources.

fltr.published.php

<?php
$linkArray = explode(',', $input);
foreach ($linkArray as $key => $resource ) {
	$page = $modx->getObject('modResource', $resource);
	$published = $page->get('published');
	if ($published){
		$publishedArray[] = $resource;
	}
}
$publishedList = implode(",", $publishedArray);
return $publishedList;
?>