This is mostly just a proof of concept for now, but it's a functional proof of concept. If anyone wants to take it and give it a try in their own mod, feel free!
Note that you will have to set up the Transition event in some way, and change the SET(x0055,x????) command in the Randoms - Victory to point at it; I recommend merging it with any other existing event that goes back to the world map when it ends. I haven't set it up to do that here myself.
I should mention up front that these event commands will make use of Variables 0x25, 0x2B, 0x3A, 0x3B, 0x3C, and 0x3D. It seems really unlikely that anyone will have used these variables for any sort of long term storage in their game, but hey.