Woocommerce Checkout - Add conditional field required if one field is filled

php wordpress woocommerce conditional-statements

PHP Snippet 1:

add_action( 'woocommerce_checkout_process', 'afm_validation' ); 
function afm_validation() {     
    if ( isset($_POST['wi_as_company']) && isset($_POST['billing_company_wi_id']) && empty($_POST['billing_company_wi_id']) ) {         
        wc_add_notice( __("Please fill company ID"), "error" );     
    }
 }