List Taxonomies: Don’t list taxonomy if it has no post – depending on custom post-meta?

This might be complicated to explain and I don’t know if there is a solution to that!?

I have a custom-post-type named “wr_event” and a hierarchical custom-taxonomy named “event_type”. The custom-post-type has a meta-box for event_date and all posts associated with this post-type are sorted by this event_date. I have one special condition in my loop to query if the event_date has already taken place – in that case it’s not shown but only listed in my archives.

Just like you can use wp_list_categories() I wrote a custom function that lists all taxonomy-terms exactly the same way.

And now my question:

When I use my custom wr_list_taxonomy() function it lists all taxonomies that have a post associated with it. Just like wp_list_categories() lists only the categories that have a post associated with it. If there would be a taxonomy-term that doesn’t have posts it wouldn’t be listed.

I wonder if it’s somehow possible to “exclude” a taxonomy-term or simply not list it if all posts associated with it have an event_date that has already taken place.

Sounds complicated right?

So I have this function that works like a charm.

function wr_list_taxonomy($taxonomy, $orderby, $hierarchical) {
    $show_count   = 0;
    $pad_counts   = 0;
    $title        = '';

    $args = array(
      'taxonomy'     => $taxonomy,
      'orderby'      => $orderby,
      'show_count'   => $show_count,
      'pad_counts'   => $pad_counts,
      'hierarchical' => $hierarchical,
      'title_li'     => $title
    );

    return wp_list_categories( $args );
}

It lists all terms and only lists them if posts are in them. However I have posts (“events” in my case) in all taxonomy-terms, but have terms whose events are all over.

And if the “events” in a term are all over (and therefore the term-page doesn’t list anything as I wrote above because I filter them by todays date) I don’t want this function wr_list_taxonomy() to print this term.

Is that somehow possible?