clear cache based on conditional action

interesting... but the cache_clear_all() does sound like kills point of caching if has to clear everything... So there is there no way to clear one node's cache? The order, in uc_order_products table has a $nid. I could just set up a separate process that checks the table every hour, and looks for new orders and does something for each node like cache_just_clear($nid), but i don't know if you can clear one node's cache as a function like that doesn't seem to exist :) ... it seems like there should be a way to do this hopefully but I can't find any info on it.

i used a custom PHP action to clear the BOOST cache like this: not sure if working 100% but anonymous user seems to see the update on the product/listing catalog pages that i wanted to show the updated stock on:

foreach($order->products as $product) {
  $nid = $product->nid;
  boost_expire_node($node = node_load($nid), $nid);
  error_log("Clearing out all alias's for node nid: ". $nid);

  //Get its related terms and expire catalog pages as well  
  $result = db_query("SELECT tn.tid FROM {term_node} tn INNER JOIN {term_data} td ON tn.tid=td.tid WHERE nid=%d order by nid", $nid);
  while ($row = db_fetch_array($result)) {
      $tid = $row['tid'];
      $path = "catalog/$tid";
      //error_log("Clearing out: ". $path);
      if (boost_is_cached($path)) {
        boost_cache_expire_derivative(array($path));
        if (BOOST_VERBOSE >= 5) {
          watchdog('boost', 'Rules flushed !page from static page cache.', array('!page' => $page));
        }
      }
  }

  //I have one view i list products on, so i simply clear this also... 

}

It depends on the user coming back to your site after checkout to Paypal which is payment method i using.