Is that possible? Hum, I have never even heard of anyone doing that. I mean yeah, I have and have seen similar consoles slaved but not anything like you want to do.
Why exactly do you want to do this? Have one as a backup? I mean in that case, I would just use an opto splitter. But if you are going to use one console for movers and the other for conventionals, why don't you just have 2 differnt DMX lines.
I had a quick look at the manuals for both boards. They both allow MIDI control using MSC. The whole hog says it should only be connected to another whole whog. There is a technote about whole hog II's earlier then a certain serial number requiring a modification to make the MIDI work. Someone like DigitalTec might be able to help you set the right messages. There could be a lot of work in this and it is quite complicated. One of the first things to do is get the manuals for both boards and read up the sections on MIDI control.
I would really like to know why you need to run these two boards as the Obsession with the latest software can operate moving lights.
Just another suggestion if you haven't already I would probably post this under the lighting question forum where more lighting people might see it.
I'm quite sure it is possible, the ML operator for the show I am doing now just linked our Hog to our obsession II, the hog has also been slaved to our express, in a different space. I know it involves MIDI cable andwas deemed surprisingly easy to do by the guys who did it, though unfortunately I was not in the booth at the time it was done. I'd say look in the manuals there should be something.