Audio Mix Control

I have been testing Manycam in the last days.
I use it to stream religious cerimonies. The set up is quite simple… we are using 3 or 4 mobile (android and iphone) phones for the whole production. Each phone has a different mic on it capturing ambience sound or someone’s microphone.
My issue is that I would prefer to manage what is my source of audio independently from the video source. Just to make it clearer: while cutting the images from a cellphone to another, I would like to have the audio source to stay the same.
Right now, I solved this by adding a layer with the cellphone with the audio source in all the presets, and sending this layer to background. So whenever I change from one preset to another, the audio remains the same.
The best option would be to have a full audio mixer within Manycam, so I could eventually mix all the audio sources as I please instead of jumping from one to another.
Do you have any suggestion regarding this issue? Any chance of this entering a future upgrade?
Thanks and best regards,