If you are on MacOS: have you heard of aggregated audio devices? It’s built into the OS and of you are not looking for a commercial product but just a tool or something for either you or your team that might be the best option. It is a pain to setup (if you compare it to Apples usual eye for detail) and doesn’t offer a hole lot of configuration. But since you are writing the application that actually uses the audio device, you should be able to make good use of it.