In windows:
Mklink /j C:\Launchbox\Games P:\ROMs\eXoDOS\eXoDOS\Games
Obviously, adjust folders as to where things actually are, but the command above would make it look like there was a Games folder inside Launchbox, but that would actually point to P:\ROMs\eXoDOS\eXoDOS\Games. To Launchbox, everything would be on drive C:. Thus:
P:\ROMs\eXoDOS\eXoDOS\Games\File.zip
And
C:\Launchbox\Games\File.zip
both point to the same file .
So, you just move the XML's, then use links to trick Launchbox into thinking those files are local.