Doing a wipe from one scene to another?

I have shot some local rugby match from which I am creating a highlights video.

I have a scene where the referee on the sideline passes directly in front of my camera from right to left, obscuring the action behind momentarily.

What I would like to do is use that as a natural "wipe", revealing a new scene as he moves across frame.

Is this easily achievable, or would it be a lot of work?

SliceX would handle this easily. What you'd do is put this clip on top of the incoming clip. Make a traveling shape mask that follows the back of the couch, revealing the clip below. Issue is, how complicated are his movements and shape, where the mask has to go.

And couldn't you also just keyframe a mask or even a crop?

Yes you could, if the edge you want is a straight line.