This is the default dual PC setup for Alias Pro in Sonar for Streamers:
PERSONAL MIX SteelSeries Alias Pro Personal (SteelSeries Alias Pro 1)
STREAM MIX SteelSeries Alias Pro Stream (SteelSeries Alias Pro 1)
MIC INPUT SteelSeries Alias Pro Input (SteelSeries Alias Pro 1)
On your second PC (Windows only):
OUTPUT SteelSeries Alias Pro Output (SteelSeries Alias Pro 2)
INPUT (OBS or other broadcasting software) SteelSeries Alias Pro Stream (SteelSeries Alias Pro 2)
How-To Video: