Separar comentarios por categoría: ¿Plugin o modificación?

$fields =  array(
    'author' => '<p class="comment-form-author">' . '<label for="author">' . __( 'Name' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
        '<input id="author" name="author" type="text" value="' . esc_attr( $commenter['comment_author'] ) . '" size="30"' . $aria_req . ' /></p>',
    'email'  => '<p class="comment-form-email"><label for="email">' . __( 'Email' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
        '<input id="email" name="email" type="text" value="' . esc_attr(  $commenter['comment_author_email'] ) . '" size="30"' . $aria_req . ' /></p>',
    'url'    => '<p class="comment-form-url"><label for="url">' . __( 'Website' ) . '</label>' .
        '<input id="url" name="url" type="text" value="' . esc_attr( $commenter['comment_author_url'] ) . '" size="30" /></p>',
	'categoria'    => '<p class="comment-form-categoria"><label for="categoria">' . __( 'categoria' ) . '</label>' .
        '<input id="categoria" name="categoria" type="text" value="' . esc_attr( $commenter['comment_author_categoria'] ) . '" size="30" /></p>'
);

$commenter = wp_get_current_commenter();
$req = get_option( 'require_name_email' );
$aria_req = ( $req ? " aria-required='true'" : '' );
$fields =  array(
    'author' => '<p class="comment-form-author">' . '<label for="author">' . __( 'Name' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
        '<input id="author" name="author" type="text" value="' . esc_attr( $commenter['comment_author'] ) . '" size="30"' . $aria_req . ' /></p>',
    'email'  => '<p class="comment-form-email"><label for="email">' . __( 'Email' ) . '</label> ' . ( $req ? '<span class="required">*</span>' : '' ) .
        '<input id="email" name="email" type="text" value="' . esc_attr(  $commenter['comment_author_email'] ) . '" size="30"' . $aria_req . ' /></p>',
	'url'    => '<p class="comment-form-url"><label for="url">' . __( 'Website' ) . '</label>' .
        '<input id="url" name="url" type="text" value="' . esc_attr( $commenter['comment_author_url'] ) . '" size="30" /></p>',
	'categoria'    => '<p class="comment-form-categoria"><label for="categoria">' . __( 'categoria' ) . '</label>' .
        '<input id="categoria" name="categoria" type="text" value="' . esc_attr( $commenter['comment_author_categoria'] ) . '" size="30" /></p>'
);
 
$comments_args = array(
    'fields' =>  $fields,
    'title_reply'=>'Titulo respuesta',
    'label_submit' => 'Eviar'
);
 
comment_form($comments_args);

function add_comment_fields($fields) {
 
    $fields['categoria'] = '<p class="comment-form-categoria"><label for="categoria">' . __( 'Categoria' ) . '</label>' .
        '<input id="categoria" name="age" type="text" size="30" /></p>';
    return $fields;
 
}
add_filter('comment_form_default_fields','add_comment_fields');

function add_comment_meta_values($comment_id) {
 
    if(isset($_POST['categoria'])) {
        $age = wp_filter_nohtml_kses($_POST['categoria']);
        add_comment_meta($comment_id, 'categoria', $age, false);
    }
 
}
add_action ('comment_post', 'add_comment_meta_values', 1);