Substack peoples, is there a way to send an email to a specific subset of people? I know you can set up a filter but it’s limited to the filters Substack sets for you.

I want the option to send an email only to people who opt into the XYZ section of Sayable, for instance, “Book Club” or “Link Love.” I know there’s a way for readers to toggle those off but is there a way for me to toggle them on for just a certain subset of people (without doing it manually…).