RTC limitation ?

Hi all,
I need to develop a VoIP application by which the server side can route incoming calls to different speakers.
Multiple sound cards will be available on the same server machine.
After delving into the Real Time Communications Client API of Microsoft, I couldn’t find any way to link audio sessions to different audio outputs programmatically. One should use the InvokeTuningWizard to enable the user to ‘select’ the audio output. But this does not help in my case.

Does anyone faced such a problem ?
Is there a way I couldn’t find to do it ?
If it is really an RTC limitation, could you please redirect me to another SDK.
Please help,

thanks a lot and best regards,

MAC