Mednafen's console/game-specific configuration settings in Playnite

[Foron]

How do I configure Playnite to run platform/game-specific commands like MedGui can? Do I copy the commands over to a box in Playnite, or do I direct Playnite to open a file?

To be more specific, I want Playnite to read my old psx.cfg file from when I tried out MedGui months ago and give me those same settings.