Would like to limit a service to a specific time slot?

I am branching out and would like to offer scheduling for discovery/strategy sessions. My normal service lasts 2 hours, but I only want the strategy session to last an hour and only be available as the first appointment of the day.... meaning, every day there is a 1 hour slot for a discovery session, but it's at 8 am. If that's booked, you'll need to pick another day.

Any thoughts on how I can make this work?