An error occurred while saving the commentanon_lurkoeb commented
As far as i am aware rtmp does not support multiple audio tracks per stream BUT rtmp supports 7.1 and according to obs twitch also supports proper 7.1 sound. That is 8 channels that can be used as 4 stereo channels or 8 mono channels or some combination of the two. That would also require software side support (OBS etc.) but should be possible.