ok, so I have the first part of the function working (1 + 2), which is:
<?php
$tgs = array();
$tgs[] = get_query_var('VST1');
$tgs[] = get_query_var('VST2');
$tags = implode(",",$tgs);
query_posts('tag='.$tags);
?>
now I just need to work it out so it displays the entire post, not just the post url, and then I’ll go from there. Any ideas?