Child of taxonomy term effecting parent term

I have multiple taxonomies attached to a custom post type, all works well on my taxonomy-xx.php page until I attempt to group the various terms into sub terms ie

term a
term b
term 1
term 2
term 3
term 4

When I group the parent to organise my terms ie

term a
-term 1
-term 2
term b
-term 3
-term 4

terms 1, 2, 3, and 4 continue to display as they should but terms a and b no longer display. Is there a parent or child setting I’m missing in my query?

<?php $term = get_term_by( 'slug', get_query_var( 'term' ), get_query_var( 'taxonomy' ) ); ?>

  <?php query_posts(array(
  'post_type'=>'community_detail',
  'community'=>$term->slug,
  ?>

Many thanks in advance.

Also I can’t get my taxonomies to page, no matter how I try. 404’s all the way. Anyone got a definitive guide?