Hi Fox85312!

If sounds like you should use the Round Robin Event Type. If you want multiple invitees to be able to book one-on-one style with multiple hosts at the same time, then you’d want to use a Round Robin Event Type. This will will pull from multiple calendars and show all availability. If one invitee books a host at 10am and the other hosts are also available at 10am, that time slot will remain on the booking page until all available hosts for that time slot are booked (depending on how you set up the Round Robin distribution - to optimize for availability or equal distribution - read more on that here!). 
The only caveat is that the third calendar will look like a separate host. This will look all the same to the invitee who is using a booking page. A word of caution with that as it may create issues with double booking with the host who has two calendars. The best way around this is to link those two calendars and have Calendly pull from just one.

I hope this helps!

Thank you, that’s really helpful. Much appreciated.