At the request of a party the court shall order witnesses excluded so that they
cannot hear the testimony of other witnesses, and it may make the order of its own
motion. This rule does not authorize exclusion of (1) a party who is a natural
person, or (2) an officer or employee of a party which is not a natural person
designated as its representative by its attorney, or (3) a person whose presence
is shown by a party to be essential to the presentation of the party's cause, or
(4) a victim of crime, as defined in Rule 39(a), Rules of Criminal Procedure, who
wishes to be present during proceedings against the defendant.