In general, the music players on phones do not account the folders. They browse through all the music on your phone and display the information in the music player irrespective of what folder the music files are in.
The information about the tracks is embedded into the files. Each music file contains a lot of information like "Artist", "Album", "Genre", "Track Number" etc. This is the information that music players read and use to organize music. Even if you have individual tracks/songs of a movie in different folders on the memory card, the music player knows and still shows them all under one album.
So, if you want to listen to music of a particular movie/album, go to the music players album view and then select the movie/album you want.
In Google Play Music, click on the 'head phones' icon on the top, select 'My Library". Here you can swipe left and right to move between 'Genres', 'Artists', 'Albums', 'Songs'