Is your feature request related to a problem?

romm expects disk based games to be in a single folder:

• Final Fantasy VII (USA)
  • Final Fantasy VII (Disc 1) (USA)
  • Final Fantasy VII (Disc 2) (USA)

I was hoping that I could use the --merge-discs option for this, as in my testing when used with extract this is how it works. The issue for me came up with Wii and gamecube games. I want to store these in the .rvz format to save space, so for these games I'm not using extract. In this case I get an error like the following:

WARN: Nintendo - GameCube: no single archive contains all necessary files, cannot move these different input files to: Games/Nintendo/Nintendo - GameCube/Metal Gear Solid - The Twin Snakes (USA).rvz:
WARN:   Games/Nintendo/Nintendo - GameCube/Metal Gear Solid - The Twin Snakes (USA) (Disc 1).rvz|Metal Gear Solid - The Twin Snakes (USA) (Disc 1).iso
WARN:   Games/Nintendo/Nintendo - GameCube/Metal Gear Solid - The Twin Snakes (USA) (Disc 2).rvz|Metal Gear Solid - The Twin Snakes (USA) (Disc 2).iso

Describe the solution you'd like

My suggestion would be that the --merge-discs option should still work without zip or extract and would just put disks within a parent folder.

Additional context

No response