Is it possible to convert an absolute path to a relative path in a batch file? (the opposite of this). Obviously you would need two inputs: the absolute path to convert, and an absolute reference path that you want it to be relativised to.
eg:
Path to convert: c:\documents\mynicefiles\afile.txt
Reference path: c:\documents
Result: mynicefiles\afile.txt
@echo off
setlocal EnableDelayedExpansion
set Path_to_convert=c:\documents\mynicefiles\afile.txt
set Reference_path=c:\documents
set Result=!Path_to_convert:*%Reference_path%\=!
echo Result: %Result%