How to ducker more than 1 source track?

Dear all. Usually i'm using audio compressor for ducking di Resolve.
This time i want to try a news ducking thing in this app.
I have first track for voice 1 and second track for voice 2, and third track for music that i want to ducked.
But the ducking just let me to choose 1 track only for the source. How about if i want to use multiple tracks for source? thanks.

ducking multiple source.jpeg (176.35 KiB) Viewed 164 times

My understanding is that in that more complicated case you are back to the multistep approach of (1) create another bus, (2) send or output channels to that new bus, (3) on the channels (or bus) you want to duck, open the Dynamics page, and turn on the sidechain with the created bus as the source.