Fade audio stream together with video on 'fade to black'?

[SettleJD]

Please forgive me, as a newbie, if this has already been covered but I have not found it.
When streaming church services I would like to be able to do a longish (5 second) fade to black and have the organ music fade at the same time. Currently, if I fade to black, the audio simply cuts at a single point in the transition. Is there a way to achieve a proper co-ordinated fade?

 

[SettleJD]

Interesting. I take it the answer is probably no, as nobody has responded in the last two weeks.
The technology is certainly beyond me but I wonder if one of the developers of add-in apps might consider having a go at this? I feel sure that there would be interest in it from others besides myself.