Actually, a batch file could quite easily be written to "add on" to this function with alot of %% signs to gather the required information that you would need to process the files. The problem with this is... you would really have to be running a SUPER computer to want to do this in the first place, as DVD processing (especially shrink) is VERY CPU intensive, and hard drive intensive as well....none the less, it could be accomplished.
Also, as SP stated above, once the program is compiled to a .exe file, you cannot simply go back and add it, you would need the source code to basically re-write the function in.
Jogso, what you are asking for, is basically, Multitasking added to the function of the program. As Laffin has stated above, it's a free program at no cost, but I'm sure if you emailed him and offered a nice DONATION he probably would consider this request.... It is extremely hard to get people to donate money for software, most just want to use it, because it's free and easy to get, and they totally forget about the author of the program. Even 2 dollars goes quite a long ways, when you have no dollars!!!!