How to select customers to send product update?

Site URL: https://francischouquet.com

Hi everyone,

I have a shop where I sell fonts. Sometimes I publish updates for these fonts. How can I select the right customers to send them the updates? When I go in profiles, I can see the customers, but I can't filter them by product. I thought I could add tags to the products but it is not related to customers. And I don't want to tag ALL my customers manually to select them by product. So how could I do that? 

Thanks,

Francis