After a customer has purchased a product from our Magento shop, he receives the invoice via email. That is working well.
Now I want to send another email, a "welcome letter", to the same email address if the customer has purchased a product of a certain category.
My question: Is there a built-in way (i.e. without PHP coding) to achieve that, tied to a product category or alike?
If not, what would be the easiest way to achieve that via PHP coding?