How can I hear all 4 outputs in MainStage using my headphones?

Mainstage advice / headphone mix

(inteface -focus rite 616)

I can only hear 2 outputs on my headphone jack input.

Ok, so my current output path from main stage  - 

output 1-2 is stereo backing track

Output 3 is a vocal mic . (using main stage for vocals so I can use vocal fx’s synched to bpm of each patch )

Output 4 - click 

Now the problem is - in ear headphone mix…

I can only hear output 1-2, or only output 3-4 ( by changing on focus rite control )

I need to hear output 1-4 ideally so I can hear music, my vocals, n click. 

So that is my question, how can I hear all 4

Thanks!!!

[Re-Titled By Moderator]