Yes, you can, but need to hack into Perl.

Assume the platform is win32, rest are similar. Goto directory site/lib/Tk/DragDrop. In that directory, there is a module Win32Site.pm. In that module, there is a sub Win32Drop(). In that sub, there is a foreach loop, and that is where, it loops through the list of all dropped files, and append them to Tk::clipboard (one of the communication channel among Tk components). You can hack your code there, obviously you have the entire list of file there and then.

The other way is to monitor clipboard.