Storage [Q] Multiple media streams on same USB sound card.

I am doing the feasibility analysis for a PC based software to be ported on Android Platform.
This requires at-least 2 sound cards connected to the Android device, i.e. Onboard Sound card (present by default), USB sound card, connected via a hub or Bluetooth.

The software requires, multiple calls to be present on the same sound card. For example, the user creates a call using the UI (Android App) and puts it on the USB sound card, and does this for 3-4 calls.
I have 2 doubts,
1. Does Android allow sound streams to be mixed on the same sound card.
2. If so does it have something similar to PulseAudio as on Linux, where by accessing the pulse sound card multiple applications use the same sound card ?