Turning powr form subscribers into specific Shopify customer segments

On Shopify, you can send emails to specific customer segments. It would be helpful to be able to send marketing email specifically only to people who specifically subscribed and signed up to a powr form, rather than to every single one of my subscribed customers over all time. It would be great to have a feature to easily send a marketing email via Shopify only to those who signed up to a specific powr form.