External Staff - Calendar sync

Hello there,

I need to create a Shared Bookings calendar and collaborate with external resources as staff. The external resource is also in M365 and has shared their calendar with me. I created the Shared Bookings calendar, but when I invite the external resource to the staff, the only option I have is to assign the “Guest” role. With the Guest role, it is not possible to avoid conflicts in their calendar because the option “Events on Office calendar affect availability” is disabled.

How can I sync my Shared Bookings calendar with the calendar of an external staff member who has already shared their calendar with me?

Best regards,

Sergio.