我想知道我是否将自定义帖子类型分组，以便在wordpress后端菜单栏中显示在一个组中，如下图所示，我必须在函数中使用什么代码。php，这样我可以给我的自定义帖子类型一个很好的外观和感觉：

<?php
/**
 * Plugin Name: Custom Functions
 * Plugin URI: http://localhost/
 * Description: This is an awesome custom plugin with functionality that I\'d like to keep when switching Themes.
 * Author: Phantom.omaga
 * Version: 0.1.0
 */

/* Place custom code below this line. */

add_action( \'init\', \'create_post_type\' );

function create_post_type() {  

/*Custom post type Series has been decleared here*/
    register_post_type( \'series\',  
        array(  
            \'labels\' => array(  
                \'name\' => __( \'Series\' ),  
                \'singular_name\' => __( \'Series\' )  
            ),  
        \'public\' => true,  
        \'menu_position\' => 40,  
        \'rewrite\' => array(\'slug\' => \'Series\')  
        )  
    );

/*Custom post type Episodes has been decleared here*/
    register_post_type( \'epsodes\',  
        array(  
            \'labels\' => array(  
                \'name\' => __( \'Episodes\' ),  
                \'singular_name\' => __( \'Episode\' )  
            ),  
        \'public\' => true,  
        \'menu_position\' => 41,  
        \'rewrite\' => array(\'slug\' => \'Episodes\')  
        )  
    );    

/*Custom post type Mirrors has been decleared here*/
    register_post_type( \'Mirrors\',  
        array(  
            \'labels\' => array(  
                \'name\' => __( \'Mirrors\' ),  
                \'singular_name\' => __( \'Mirror\' )  
            ),  
        \'public\' => true,  
        \'menu_position\' => 41,  
        \'rewrite\' => array(\'slug\' => \'Mirror\')  
        )  
    );   

}  


/* Place custom code above this line. */
?>