Using subgroups and outputs

Hoping someone can help me out. I have a UR824 and using a DAW called Livetracker connected usb. Livetracker allows you to assign each track to a subgroub, and I want to send each group to the ur824 line out puts, so track one goes to line out 1/2 track 2 goes to lineout 3/4 and so forth. all I can get is mainmix out of the ur to my mixer on line 1/2 not the individual subgroups. any Ideas what I am missing?