excluding a $feed_item from node_processor

I am writing a feedapi processor which will run before the node_processor to import feed items as nodes.
I've got it all set up and firing properly on each action on the feed node.

I basically want to 'drop' an item in the feed if a certain condition is met, for example, if tag = foo.
I've managed to catch the condition in my processor, but when i set $feed_item = new stdClass(); or $feed_item = null; to delete the feed_item when node processor then runs after my custom processor it still imports all the feed items.

how can i 'exclude' these feed_items or delete them from getting added in the node_processor.
my module is setup correctly and my processor is definitely firing before node_processor.

heres my code -

  function module_feedapi_save($feed_item, $feed_nid, $settings){
    switch($feed_item->options->tags['0']{
      case 'tag':
        $feed_item = null;
        return $feed_item;
    }
  }

i could explicitely call _feedapi_node_save(); from within my module, after i unset the feed_item, but this doesnt seem like the best way to approach things, since if i do this, i will have to disable it on the content type, and my custom module will need to fire off all the feedapi_node modules nodeapi hooks.

any ideas?