i have played around with mm link function, and i have to say first, aldos, nice idea (wonder why i haven't thought about it myself).
but then i must say, it does not work, at least not with the 4.x releases, as only mm can see these links.
i have tried the old one 2.09, as i have it still as an install to another folder (BLES80607) because of its awesome shadowcopy function, and i must say, it WORKS.
i have only tried internal hdd so far, by placing codebreaker in seperate folder naming disc1:
dev_hdd0/PSXGAMES/Codebreaker/disc1.bin and cue
the game i've tried, here alundra, i placed in regular gamefolder:
dev_hdd0/PSXGAMES/Alundra/disc2.bin and cue
then i have shadowcopied with old mm 2.09 the codebreaker disc1.bin and cue to the alundra gamefolder.
irismanager does really accept this shadowcopy as regular disc1 and gives the disc selection screen when selecting alundra to start and fires up the codebreaker. after pressing start in codebreaker i only unplug now unused usb hdd and replug and press O as soon as plugged and it really starts alundra.
the advantage of the old mm 2.x is, it shadowcopies to any folder and not only this desktop folder under mm directory like the 4.x releases...