List Pages with Specific meta key/value Help PLEASE?

Trying to use wp_list_pages() to generate a list of Pages, listing <b>only</b> those Pages with a specific meta key value (custom field value).

So far, I’ve got this:

< ? php
     // get the meta value for the key 'foo'
     $Cluster = get_post_custom_values('foo');

     // make sure that worked
     print_r($Cluster);  // I'm ok here, so far

     // if $Cluster not null, list the Pages with the custom key 'foo' and the value 'bar' THIS IS WHERE IT DOESN'T WORK:
     if ($Cluster !== '') {
          echo '<div class="article_links"><h4>Learn More</h4><ul>';
          wp_list_pages($Cluster);
          echo '</ul></div><!-- .article_links -->';
     }
     ?>

Passing the $Cluster argument to the wp_list_pages function only results in an ul of ALL pages, not a list of Pages with only the key/value I want (foo/bar) in this example.

The wp_list_pages page of Codex states I can use the function

“restricted to Pages with specific meta key/meta value (not shown in defaults above)

does ANYONE have an example of the correct syntax for wp_list_pages that restricts the list to Pages with specific meta key/values????

PLEASE??

Thanks in advance.