Best way to set up 4 separate candidate interviews with a panel of 4 interviewers

There are a few ways to handle this: 

• Schedule 4 different meetings, one for each candidate. The invite for each candidate's session is sent to/on the calendar of each interviewer. They join each session as they need. 
• Schedule 1 session for all candidates and just utilize Waiting Room to allow 1 candidate in at a time. When in the waiting room, you are not aware of any others in the waiting room with you, so there is no worry about candidates seeing/hearing/being aware of each other. The interviewers will remain for the entire session, or can come as go between each session. 

Hope that helps and please make sure to mark the solution as accepted if this information is what you needed.