Never used 3 but I have used two, SB Audigy ZS + Bluetooth Headset. You need applications that will allow you to setup the preferred device(audio out stream) seperate from the standard windows control (Winamp, Teamspeak for sure, some games). As long as it is a static device and windows doesnt reset your sound options every once in a while it should work fine. I finally gave up on my setup, everytime my bluetooth started acting up it would drop the stream and require the device to be repeered, and possibly reset my prefered device in my control panel to bluetooth.
It is my opinion that windows isn't ready for multiple sound cards. I'd love to be able to just turn my bluetooth headset on for a moment without having to worry about screwing my other settings, or if the headset looses connection for a moment I can easily recover instead of having no sound until I reconnect and restart all applications using the device. Also a lot of applications arn't aware of multiple sound cards and only look for the preferred device.