WooCommerce Filter Orders by Item Count - php

Question

Is it possible to create a custom filter in WooCommerce Orders Admin which will allow filtering by the order item count?
We are looking to filter orders with either one item or more than one item (multiple items).
We have the dropdown on the page via the following action and function, but we're stuck on the filter part and how to query each order to find the item count.
add_action( 'restrict_manage_posts', 'filter_multi_item_orders', 50 );
function filter_multi_item_orders() {
global $typenow;
if ( 'shop_order' != $typenow ) {
return;
}?>
<select name='multi_order_view' id='dropdown_multi_order_view'>
<option <?php
if ( isset( $_GET['multi_order_view'] ) && $_GET['multi_order_view'] ) {
selected( 'all', $_GET['multi_order_view'] );
}
?> value="all"><?php esc_html_e( 'Single and Multi Orders', 'show_multipet_orders' ); ?></option>
<option <?php
if ( isset( $_GET['multi_order_view'] ) && $_GET['multi_order_view'] ) {
selected( 'single', $_GET['multi_order_view'] );
}
?>value="single"><?php esc_html_e( 'Single Orders Only', 'show_multipet_orders' ); ?></option>
<option <?php
if ( isset( $_GET['multi_order_view'] ) && $_GET['multi_order_view'] ) {
selected( 'multi', $_GET['multi_order_view'] );
}
?>value="multi"><?php esc_html_e( 'Multi Orders Only', 'show_multipet_orders' ); ?></option>
</select>
<?php
}
add_filter( 'request', 'filter_multi_item_orders_query', 100 );
function filter_multi_item_orders_query( $vars ) {
global $typenow;
$key = 'post__not_in';
if ( 'shop_order' == $typenow && isset( $_GET['multi_order_view'] ) ) {
if ( 'single' == $_GET['multi_order_view'] ) {
// return orders with $order->get_item_count() == 1
}
elseif ( 'multi' == $_GET['multi_order_view'] ) {
// return orders with $order->get_item_count() > 1
}
}
return $vars;
}
This may not be the best/a possible approach but hope someone can shed some light.
Many thanks