How to redicect single audio channels to different devices?

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http://askubuntu.com – I just bought a bluetooth stereo speaker and I had an idea: Is it possible to build a 4.0 audio system using my Bluetooth speakers as rear speaker and two normal cabled stereo speakers (or another pair of bluetooth speakers) as front? Which program I have to use? In general: is it possible to split a 4.0 or 5.1 signal in the single channels and send them to multiple devices? Thank you! (HowTos)