Hello. How do i create a splitscreen with a white line separating the two?

Hello all! Its my first post and im new to editing so be gentle. Im trying to do a splitscreen with a white line separating the two shots in FCP 6. half-way through the spot one of the actors is going to hit the white line and i want it to wipe across half the screen. Please help im on a super strict timeline and i cant figure it out. THANK YOU!!!!!

P.S. if anyone has a good way to color correct a vide to look 80's style that would be great.... Thanks.

Alex