I am looking for a way to set up a smart list to trigger a response email based on if someone already exists in Marketo or if they are new. The existing members will be prompted to update their profile and subscription preferences while the new members will be asked to complete their profile and enter their subscription preferences via email. I've seen a somewhat similar situation with a solution, but am not sure if it will work the same way.
If it's the same campaign, do the evaluation in the flow as a choice. If "Person was Created" in past "30 minutes" <--- choose whatever you like here in terms of time, then send new user email. Default is to send the existing lead email.