Hello, I have two interfaces like Steinberg MR816 CSX and 4 stereo outputs set the control room of cubase 5 … anyone know how to address two on each interface? … the idea is to have 4 mix headphones for musicians and a general mix to monitor the room where it operates. thanks 
Hi
I have the same setup with 4 headphone mixes and I have done it this way:
1.Create 4 subgroup channels: Submix 1-4 or whatever name. Set the output of these 4 to your 2x2 MR stereo outs
2. Use four sends on each of your existing input channel an route them to the 4 subgroups
3. In the Audio Hardware setup select your as source 2x2 for the 4 headphones ( one to each ).
You can now make an individual mix by controlling the sends on each input channel.