Change Woocommerce checkout to process order on an separate WordPress site?

I need to create how Woocommerce handles orders so I can create an order on Site A and send that order to Site B.

So when customer adds items to their cart and click checkout, it creates the order on both Site A and Site B, however, it also redirects the user to Site B to process the payment.

So far I can only change the checkout button:

add_filter( 'woocommerce_get_checkout_url', 'my_change_checkout_url', 30 );

function my_change_checkout_url( $url ) {
   $url = "your checkout url ";
   return $url;
}

and creating the order.

if (isset($_POST['isOrder']) && $_POST['isOrder'] == 1) {
    $address = array(
        'first_name' => $_POST['notes']['domain'],
        'last_name'  => '',
        'company'    => $_POST['customer']['company'],
        'email'      => $_POST['customer']['email'],
        'phone'      => $_POST['customer']['phone'],
        'address_1'  => $_POST['customer']['address'],
        'address_2'  => '', 
        'city'       => $_POST['customer']['city'],
        'state'      => '',
        'postcode'   => $_POST['customer']['postalcode'],
        'country'    => 'NL'
    );

    $order = wc_create_order();
    foreach ($_POST['product_order'] as $productId => $productOrdered) :
        $order->add_product( get_product( $productId ), 1 );
    endforeach;

    $order->set_address( $address, 'billing' );
    $order->set_address( $address, 'shipping' );

    $order->calculate_totals();

    update_post_meta( $order->id, '_payment_method', 'ideal' );
    update_post_meta( $order->id, '_payment_method_title', 'iDeal' );

    // Store Order ID in session so it can be re-used after payment failure
    WC()->session->order_awaiting_payment = $order->id;

    // Process Payment
    $available_gateways = WC()->payment_gateways->get_available_payment_gateways();
    $result = $available_gateways[ 'ideal' ]->process_payment( $order->id );

    // Redirect to success/confirmation/payment page
    if ( $result['result'] == 'success' ) {

        $result = apply_filters( 'woocommerce_payment_successful_result', $result, $order->id );

        wp_redirect( $result['redirect'] );
        exit;
    }
}

Though I'm not sure how to put all of this together so I can work with both Site A and Site B.

How can I do this?

from Change Woocommerce checkout to process order on an separate WordPress site?