I see you are already pretty advanced in programming! :).
Unfortunately, the screenplay is currently really basic, so you will have to repeat your dialogue for now :(.
But for the future, I think the and/or solution is best for the situation you are describing. But don’t count on that being implemented soon.
My global plan for the screenplays is to have a fully Object Oriented programming language in there, where you can do anything you want (as in any other programming language). And I know a way how to keep things really simple for beginners :).