How to trigger Follow Up with existing email addresses?

Ciao. I have about 1,500 emails from past customers that I would like to use with the Follow Up process.

First, I have an email that uses the {subscription_confirm_url} field to update the contacts Status from ‘Not Confirmed’ to ‘Confirmed’. Then once the past customer is confirmed, I would like the Follow Up process to start.

Is there a way to do this? Or maybe a different confirmation process I should use?

Jeff