UR816C: How do I get the Cubase master output on the Mix2… Mix4 DAW slider?

Hello dear UR816C users,
I connected wireless headphones to each of the outputs of Mix2, 3 and 4. During a band session, the band members can put on headphones if necessary and level themselves and the other instruments individually.
Unfortunately I can only mix in the DAW master output on Mix1. If I want that on Mix2 to 4, I can only do that by adding an additional mix route to every existing track in Cubase. This is extremely time-consuming for what is actually a simple wish: How do I get the complete DAW master output on the DAW sliders of Mix2 to 4 in a simple way?
Thank you for tips!

Ok, this is answered. I have to use the “control room”