I'm curring working on a lisp to re-path xrefs whenever you open a drawing.
but |I don't have a lot of time for it at the moment.
I know the xref path has a dxf code of 1, so it's a matter of extracting it as a string, changing the string to show the new path and then using the -xref command to change it, but I don't know when I'l get time to finish this though.