Pixel Streaming 2: How to separate audio per stream for multi-language characters? (Submix routing)

Hello everyone,

I am working on a project in Unreal Engine 5.6 featuring multiple characters who speak different languages simultaneously. My goal is to stream these characters into separate WebRTC streams using the new Pixel Streaming 2 plugin.

The Problem: Currently, I am unable to isolate the audio for each individual stream. Pixel Streaming 2 seems to capture the global Master Audio/Master Submix of the level by default. Because of this, every stream receives the combined audio of all characters speaking at once, rather than a dedicated language track per stream.

What I need to achieve: I need to route Character A’s audio (e.g., English Submix) exclusively to Streamer 1, and Character B’s audio (e.g., Spanish Submix) exclusively to Streamer 2.

My Questions:

  1. Is there a built-in way in Pixel Streaming 2 to specify a target Sound Submix for a specific Streamer component/ID instead of capturing the Master Submix?

  2. If not natively supported yet, could someone point me to where in the C++ source code of the Pixel Streaming 2 plugin (or EpicRtc) the audio listener/mixer hook is implemented, so I can attempt to modify it to filter by Submix?

Any advice, workarounds, or code snippets would be greatly appreciated!

Thank you in advance!