There is a feature on the add a secondary machine screen called Monitor Control (Shares With).
I think the implication is this:
Monitor 1 - Monitor 2
|...........|......|
comp1 Comp2
The diagram is attempting to show one monitor connected to Computer1 and both monitors connected to computer2. The drop down choices under monitor control imply that this is possible but there is no mention in the documentation.
So, is it possible?
Thanks,
Drew