The problem with this, is that you’d need to communicate between the halves.
This is certainly possible, but it’s not set up to do so. Namely, the cable between the two does serial. If it did I2C (which the screen does), and both Pro Micros and both Screens had addresses assigned to them, you could do this easily.
As is, you’d have to edit the split files to enable communication between the boards, and basically write some sort of sub-protocol for writing to the other screen.
Both are possible, I think. But this isn’t “simple” by any stretch. Unless you’re an experienced C and embedded hardware programmer.