@Hemdale Hello
the best way you can do it is to create a .m3u file :
https://forum.recalbox.com/topic/17108/compiler-multi-disquettes-ordinateurs-en-une-rom-unique/10?_=1594625238342 - in french but there are examples ^^
And then you scrap only .m3u files.

@speedshark13
Corrigé pour 6.1
https://gitlab.com/recalbox/recalbox/blob/master/RELEASE-NOTES.md#fixes

Fix Amiga multi-disk bug with [] characters

Bonjour @voljega
bkg2k a résolu le problème , se sera dispo en 6.1
https://gitlab.com/recalbox/recalbox/blob/master/RELEASE-NOTES.md#fixes

Fix Amiga multi-disk bug with [] characters

@voljega salut
jai pas de jeux msx mais si m3u est dispo faut essayer.
https://docs.libretro.com/library/bluemsx/

Edit
@voljega j'ai trouvé ceci : as tu essayé ?
Core Disk Options > Disk Image Append