Where Thunar may struggle with your needs the command line will not. To illustrate this I have created a directory filled with 'pythonesque' files, except for one:
andrew@illium~/test$ ls -1
Now to copy all of the python related filenames to another directory, leaving our non-python file uncopied:
andrew@illium~/test$ cp -v *python* $HOME/another_directory/
'blah_blah_python.jpg' -> '/home/andrew/another_directory/blah_blah_python.jpg'
'python_rulz.txt' -> '/home/andrew/another_directory/python_rulz.txt'
'test_python.txt' -> '/home/andrew/another_directory/test_python.txt'
Note that the non-python named file has been excluded. Perhaps this will suit your needs better rather than trying to massage Thunar beyond its modest capabilities?