Note: If you play a 5.1 file through standard stereo headphones or basic TV speakers, the media player will "downmix" the audio to 2.0 channels, defeating the purpose of the surround mix.
I should check if there are official sources providing these tracks. Maybe Bollywood releases with 5.1 audio, so looking into albums or partnerships between music labels and Dolby. Also, possible torrents or unofficial sources, but need to mention legal aspects and copyright issues. Dolby Digital Ac3 5-1 Audio Hindi Songs -UPD- Download