Can the AR series mixers be cascaded?

Can the AR USB series mixers be cascaded or used simultaneously. I'm looking for a mixer that I can do live recording/mixing on the occasion. (I have the RM31ai, Studio One 3.2 etc. in the studio) So the AR looks to be a perfect addition to my arsenal. However, I'm conceed that the AR16 USB may be not quite big enough, too bad there isn't a 24. So my thought was a 16 and a 8 would be great.

Thanks,

James