Limit only shipping states (provinces) but not billing states in WooCommerce

I have the following code which limits the provinces to Valencia (Spain) only, in WooCommerce:

add_filter( 'woocommerce_states', 'tl45r_custom_woocommerce_states' );

function tl45r_custom_woocommerce_states( $states ) {

    // Only show specific provinces (Madrid - MD and Barcelona - B) for Spain (ES)
    $states['ES'] = array(
        //'MD' => __( 'Madrid', 'woocommerce' ),
        //'B'  => __( 'Barcelona', 'woocommerce' ),
        'V'  => __( 'Valencia', 'woocommerce' ),
    );

    return $states;
}

However, I want this limitation only be applied to the shipping field but not the billing field.

How can I do this?