netflix and chromecast and sound to usb/bluetooth ?

Hi people,

i recently saw your application and love to use it with chromecast and netflix but I tried hard getting it to run, without success  
I simply tried everything but don't get the appliation to route the netflix sound to the different source of my smartphone.

How can I make it happen that if I click "cast screen" that only the video is streamed and sound is redirected to the mobile phones devices connected via bluetooth or usb ?


best, Tamer

Hardware:
soundblaster E5 (bluetooth or usb connect)
chromecast 4k
FullHD 24 inch LED monitor

Software:
Google Home
Netflix