Multiple taxonomies and meta query with url parameters

Hi,
I’m working on a new website for one of my client and I’m trying to do something which happens to be more difficult than I expected. I’ll try to do my best to explain what I’ve done and what I want to do.

I’ve got a list of “people” (custom post type) working on some radios, that I want to display, and I want to let the user order and filter the results by meta and tax query. He can choose the following taxonomies thanks to 3 dropdown lists : radio, show, column (all 3 are taxonomies). In addition, he can select the sex (male/female, custom field), and the order of the results.

The way I try to display the good results is by getting the url parameters and use them in the query_posts like this :

<?php

<!-- Get the paramaters  -->
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
if( !empty($_GET['order']) ) $order=$_GET['order'];
else $order='ASC';
if( !empty($_GET['sex']) ) $sex=$_GET['sex'];
if( !empty($_GET['radio']) ) $radio=$_GET['radio'];
if( !empty($_GET[‘show’]) ) $show=$_GET['show'];
if( !empty($_GET[‘column’]) ) $column=$_GET['column'];
if( !empty($_GET['name]) ) $name=$_GET['name]; 

<!-- If at least one paramater exists  -->
if (($sex && $radio || $show || $column) || ($radio || $show || $column)) {

	query_posts(array(
		'post_type' => 'people',
		'orderby' => 'title',
		'order' => $order,
		'posts_per_page' => 25,
		'paged' => $paged,
		'meta_query' => array(
			array(
				'key' => 'sex',
				'value' => $sex,
				'compare' => '==' )
				),
		'tax_query' => array(
			array(
				'taxonomy' => 'radio',
				'field' => 'slug',
				'terms' => $radio,
				),
			array(
				'taxonomy' => 'show',
				'field' => 'slug',
				'terms' => $show,
				),
			array(
				'taxonomy' => 'column',
				'field' => 'slug',
				'terms' => $column,
				),
			)
		));

} else {

	query_posts(array(
		'post_type' => 'people',
		'orderby' => 'title',
		'order' => $order,
		'name' => $name,
		'posts_per_page' => 25,
		'paged' => $paged,
		'meta_query' => array(
				array(
					'key' => 'sex',
					'value' => $sex,
					'compare' => '==' )
					)
		));

};

if ( have_posts() ) : ?>

But here is my problem : if all the parameters are filled, the query works. But if the user only choose the sex, or the ??radio??, or even multiple parameters but not all, the query does not work. I have to make it work in all situations, and with every paramaters possible, whether the user selected them or not.

For example : display people that are male, and working on VirginRadio, in the Morning Show. Or only people that work on VirginRadio. Or only females in every radios…

Do someone know how I could do that ?

Thanks ??