Adding hardware Processing to sub mixes

This is a Cubase question but I had to mention other equipment to explain what I am looking to do.
I am considering the purchase of a D-box summing mixer. My UAE interface only has 8 outs, so I am planning to create 4 stereo sub mixes in Cubase, then port them through the interface to the Dbox, and onto other processing HW, then back into a stereo main mix in Cubase. So for this example, lets say I create 8 tracks of drums. I would use individual track insert plugins for EQ and compression, and then all of those tracks would go to a group track (or a sub mix). Some of the tracks I would create a send for reverb, would

??? would…???