Custom group of subscribers

Users should be able to create a custom group of subscribers. For example, if I want to send an email to people who haven’t purchased Product XYZ, I should be able to filter subscribers and create a custom group to send email

YESSSSS! I want to send an email to current subscribers, who aren’t still on the free trial, or vice versa, or subscribers of the higher tier but not the lower one, and It’s not possible. It’s so frustrating.