Reply to Two S2s into 1 Z2 (Back to Back DJing)

Is this possible to do? Say one S2 is plugged into the first channel of the Z2, the other S2 into the second channel. One S2 is mixing on decks A and C, the other is mixing on B and D. Each S2 is able to freely mix two tracks through the Z2; then say the first S2 is going to transition into the second S2, use the effects on the Z2 to transition to. Then bringing the crossfader over to the right and now the second S2 is freely mixing it's two decks.

Searched and didn't find anything.

Any help would be appreciated.