If it's intended to be an occasional segment and not the full format of the show, you could easily get away with picking up the shotgun mic module for the H6 and passing the unit back and forth reporter-style. OR use the omnidirectional module (That usually comes with it) and set it up in the middle of the car.
(Basically, if it's a segment of a larger interview show, then you can get away with a more 'live in the field' sound because you'd be pointing out that it's a 'live in the field' segment.)