Multiple Custom Permalink Structures in Wordpress

I have one Custom Post Type 'story' and two taxonomies, 'artist' and 'writer'.

I have managed to get a Custom Permalink Structure like /%artist/%writer%/%story% by doing this (resumed code):

    add_action('init', 'custom_init');
    add_filter('post_type_link', 'story_permalink', 10, 3);

    function custom_init(){  
        $story = array(  
        'query_var' => true,
   开发者_C百科     'rewrite' => false,
        );
        $artist = array(
        'query_var' => true,
        'rewrite' => true
        );
        $writer = array(
            'query_var' => true,
            'rewrite' => true
        );  

        register_post_type('story', $story);
        register_taxonomy('artist', 'story', $artist);
        register_taxonomy('writer', 'story', $writer);

        global $wp_rewrite;
        $story_structure = '/%artist%/%writer%/%story%';
        $wp_rewrite->add_rewrite_tag("%story%", '([^/]+)', "story=");
        $wp_rewrite->add_permastruct('story', $story_structure, false);
    }

    function story_permalink($permalink, $post_id, $leavename){
        $post = get_post($post_id);

        $rewritecode = array(
        '%artist%',
        '%writer%',
        $leavename? '' : '%postname%',
        $leavename? '' : '%pagename%',
        );

        if('' != $permalink && !in_array($post->post_status, array('draft', 'pending', 'auto-draft'))){

            if (strpos($permalink, '%artist%') !== FALSE){
            $terms = wp_get_object_terms($post->ID, 'artist');  
            if (!is_wp_error($terms) && !empty($terms) && is_object($terms[0])) $artist = $terms[0]->slug;
            else $artist = 'unassigned-artist';         
            }

        if (strpos($permalink, '%writer%') !== FALSE){
            $terms = wp_get_object_terms($post->ID, 'writer');  
            if (!is_wp_error($terms) && !empty($terms) && is_object($terms[0])) $writer = $terms[0]->slug;
            else $writer = 'unassigned-writer';         
        }           

        $rewritereplace = array(
            $artist,
            $writer,
            $post->post_name,
            $post->post_name,
        );
        $permalink = str_replace($rewritecode, $rewritereplace, $permalink);
        }
        else{
        }
        return $permalink;
    }

That gives me something like /jason/john/the-cat-is-under-the-table.

But the structures that I really need are:

/artists/%artist%

/writers/%writer%

/stories/%story%

Maybe is too easy, but can't really figure out how to get this done because I don't know how to deal with Custom Post Types and Taxonomies in an homogeneized Custom Permalink Structure.

Any help to solve this will be greatly appreciated.