You'd need a PSX tool that can separate layers. I know of none but X GOD mapped X4 without flaw so you could ask him.
Example:
https://www.vgmaps.com/Atlas/PSX/MegaManX4-SkyLagoon-Area1.png
Example:
https://www.vgmaps.com/Atlas/PSX/MegaManX4-SkyLagoon-Area1.png