I would like to make a simple playlist in VLC where the first file is loaded randomly from folder "A", then the second one randomly from folder "B", then loop from beginning and load different files from the folders. The problem is that the VLC expand the folders and plays all the files in them. How can I make such a playlist?
You can't. VLC Documentation on Playlists.
You could manually sort it (not random) or you would need to use two players. One playing folder A and one playing folder B.