Track responded emails in Tracking Report
There is currently no way to track responses to emails. It would be ideal to track in the 'Open tracking report'.
As a follow-up campaign, only send emails to those who have not replied. And to confirm details to those that have accepted an invitation or responded, a separate email campaign.
This feature is now available: https://support.yet-another-mail-merge.com/hc/en-us/articles/115003111369