There is a tool created some years ago to rip Playstation games from their ripped .iso format to the all contained .pbp format that was created for the PSP. The following link is the tool:
This tool can be used to create single file games from multi-disc Playstation titles such as “Legend of Dragoon” and others that is natively read by epsx-rearmed in the retroarch package. This has the added benefit of removing the multi-disc issues that plague some of the current games.
This could be one possible solution to the multi-disc issues for Playstation games at least. Attached below is a file I’ve uploaded to a google drive that was once a 4 disc title that has been condensed to a single .PBP file.