$data{$sub_alias}{$topic_sub}{$id}{ 'URL' } = 'my_url';
$data{$sub_alias}{$topic_sub}{$id}{ 'TITLE' } = 'mytitle';
$data{$sub_alias}{$topic_sub}{$id}{ 'CONTENTTYPE' } = 'my_type';
$data{$sub_alias}{$topic_sub}{$id}{ 'SUBCATEGORY' } = 'my_sub';
$data{$sub_alias}{$topic_sub}{$id}{ 'TOPIC_DESCRIPTION' } = 'my_desc';
$data{$sub_alias}{$topic_sub}{$id}{ 'RELATED_TOPICS' } = 'my topic';

##</code><code>##

foreach $tmp_sa (@foo)  {

   foreach $t (@bar)..... {

      foreach ( keys %{$data->{$tmp_sa}{$t}} ) {
         print "$data->{$tmp_sa}{$t}{$_}{'URL'}\n";
      } 

   }

}