The below code snippet can be used tor –> functions.php.
In the above snippet, we can see that there are groups formed.
One group has been given the name “Mail Express” which contains the services “EXPRESS_MAIL” and “flat_rate_box_express”.
Similarly, another group is “Standard Mail” and contains “FIRST_CLASS” and “STANDARD_POST”.
So the snippet will search the cheapest rates among the services under “Mail Express” and “Standard Mail” and then display those in the cart page.