address belong belongs buyer customer email group groups multiple newsletter newsletters product products purchased receive receives sell send single website

Hi. I sell multiple products from one website. I want to send newsletters to people who have purchased more than one product. This means they would belong to multiple product groups. I want to send a newsletter to each product group. I only want them to receive one newsletter email from me, not one email for each product. So how do I send a newsletter to multiple product groups and make sure each customer only receives the one email?

Even if an email address belongs to more than one buyer group, they will still receive a single email.