filter_woocommerce_json_search_found_customers.php

add_filter( 'woocommerce_json_search_found_customers', 'my_woocommerce_json_search_found_customers', 10 , 1 );
function my_woocommerce_json_search_found_customers ( $found_customers ) {
	
	foreach ( $found_customers as $key=>$customer ) {
		// use id to check if user is VIP
		$is_a_member = false;
		require_once( ABSPATH . 'wp-includes/pluggable.php' );
		if ( $group1 = Groups_Group::read_by_name( 'VIP1' ) || $group2 = Groups_Group::read_by_name( 'VIP2' ) ) {
			$is_a_member = ( Groups_User_Group::read( $customer->ID , $group1->group_id ) || Groups_User_Group::read( $customer->ID , $group2->group_id ) );
		}
	
		if ( !$is_a_member ) {
			unset( $found_customers[$key] );
		}
	}
	
	return $found_customers;
}