Drupal AHAH Question

I think this is my fourth attempt to master AHAH. I think this time I am getting pretty close to AHAH zen… but I have a question I was hoping someone could help with.

I have created a form that has a taxonomy select item and two other page elements.

I simply want to add or remove one of two page elements depending on the selected value. I can easily do this with jQuery, but I think this is a good exercise for me to finally figure out AHAH.

My two form elements:

$form['resource_type']['element_one'] = array(
  '#type' => 'textfield',
  '#title' => t('Element One'),
  '#size' => 60,
);

$form['resource_type']['element_two'] = array(
  '#type' => 'textfield',
  '#title' => t('Element Two'),
  '#size' => 60,
);

I am using form_alter to add the AHAH to the taxonomy:

function module_form_alter(&$form, $form_state, $form_id) {
    if ($form_id == 'resource_node_form') {
        $form['taxonomy'][1]['#ahah']['path'] = 'resourceType/js';
        $form['taxonomy'][1]['#ahah']['wrapper'] = 'resource_type';
        $form['taxonomy'][1]['#ahah']['effect'] = 'fade';
    }
}

And my callback so far looks like:

function resource_type_js(){
    $form_state = array('storage' => NULL, 'submitted' => FALSE);
    $form_build_id = $_POST['form_build_id'];
    $form = form_get_cache($form_build_id, $form_state);
    $args = $form['#parameters'];
    $form_id = array_shift($args);
    $form_state['post'] = $form['#post'] = $_POST;
    $form['#programmed'] = $form['#redirect'] = FALSE;
    drupal_process_form($form_id, $form, $form_state);
    $form = drupal_rebuild_form($form_id, $form_state, $args, $form_build_id);
}

I am stumped on how to remove one of the two form elements. Any help would be really appreciated.

Thanks!