Followup for SEND INVITE email

When I send an invite I want to automate some followup in case they do not use the link and book. Please note this is not after they book. Ive got that.
This is I send the invite, they don’t use it, I need a reminder to check on them. I can;t see any way to trigger a tag or any other automation.
We could any number of these in a conversation day and I would otherwise need to create another followup system. Not good automation!!
Any suggestions.