Hot to allow multiple staff bookings but always include one specific staff (meeting room)

I can`t figure out how to to this.
I have a demo booking link with 4 staff members. For every booking, one staff is selected randomly based on their availability.
I want to add one staff (meeting room email address) by default to all those demo bookings.

So that when someone books a time from that calendar one random staff member is included + the meeting room

Help...