Working with rssposter_parse_rss hook

[AndrewRich]

I'm trying to implement a source blocklist for our RSS feeds - we get newsfeeds from Google News and rather than trying to figure out Google's broken news-source nomenclature, I will just block items from unwanted sources from posting. I'm hooking rssposter_parse_rss and have defined a blocklist as $vbulletin->options['rssitemsourcefilter_blacklist']. Here's my plugin code so far:

PHP Code:

global $vbulletin; 

if ( $vbulletin->options['rssitemsourcefilter_enabled']) { 
  $blacklistA = preg_split ( '/\s+/', $vbulletin->options['rssitemsourcefilter_blacklist'] ); 
  foreach ( $blacklistA as $blacklist ) { 
   if ( stripos ( $item['link'], $blacklist ) !== FALSE ) { 
     // link source appears in blacklist 
     if (defined('IN_CONTROL_PANEL')) { 
       echo "<p>RSS feed item with source {$blacklist} was blocked.</p>"; 
     } 
     $item = NULL; // nullify the RSS item 
   } // if 
  } // foreach 
} // if 


This does "empty out" the particular RSS item but it doesn't actually remove it from the queue, so instead a blank entry with a no-destination "more" link is posted. I've been going through /includes/class_rss_poster.php and /includes/cron/rssposter.php to try to figure out how to actually remove the offending item, but without any luck.

Any help appreciated. Thanks.