Hello!
I recently switched from a UR44 to a UR28m. Awhile ago on this forum, I was told that this would be possible.
The owner’s manual seems vague. I am not getting simultaneous sound out of all six outputs with a different signal. What do I do?
There are numerous posts explaining this. Use the search function 
e.g. UR28M Outputs/Routing - #11 by BriHar - Steinberg Hardware - Steinberg Forums