Yes, this is my live setup:
Audio: There's an OT, a G2 Engine, and a little Rolls mixer.
G2 Main Outs--> Mixer Ch. 1
OT Cue outs-->G2 Aux Ins-->G2 Aux Outs-->Mixer Ch. 2
OT Main Outs-->Mixer Ch. 3
MIDI: There's OT, G2 Engine, Remote Zero, and iphone w/ Missing Link.
OT MIDI Out-->Missing Link hardware input
iphone-->Missing Link wireless input
Missing link output-->Remote Zero Input
Remote Zero Output-->G2 Input
G2 Output-->OT Input
The MIDI is a bit complicated, but the OT's MIDI output, plus iphone's MIDI, plus Remote Zero's MIDI are all added up and sent to the G2 to sequence and to get MIDI remapped and sent to the OT.
So, yeah, that's one way. I love it.