Yes, you can.

1. Create a new folder within the Photos hub (e.g. whatsapp mp3s).
2. Copy any song from ur music folder into that new folder.
3. Rename it from *.mp3 to *.mp4
4. Go to whatsapp, send an attachment (select video).
5. Select the songs within the folder u created earlier. Dont worry, it will detect as a video, but the receiver will detect as an mp3 song file.
6. Send.