UR44 Setup with Stereo Speakers + Mono speaker (into ProTools or using a music player too)

Hello, i’m a windows 7/protools/cubase/studio one/foobar2000 user. I’m having a hard time feeding a mono signal to a Mixcube (mono speaker). Plus, my stereo speakers are connected at the same time. I don’t see a way to sum to mono Line Out 1-2… Is this possible?

I know Line outputs 1-2 are actually a MAIN duplicate. I could use that with a 2nd set of stereo speakers (i’m planning to do that very soon).

I’d like to know how can i achieve this with my UR44. Right know i need to have a set of stereo speakers + mono Mixcube. And i’m planning to use 2 set of stereo speakers + mono Mixcube.

Shall I keep my UR44? Do I need 6 REAL independent outputs?

Thanks!
Nahuel