monitor sharing & extended desktop on a local network

WIth an external monitor connected to a Macbook Pro laptop (or several monitors to a Mac Pro desktop) you can either mirror the display or create an extended desktop of neighboring monitors.

With screen mirroring (in sharing preferences) you can control another computer through a mirror of the remote computer's screen on your (the controlling) computer's screen.

How (if you can) would you setup an extended desktop to slide the cursor from your computer to the computer whose screen you are sharing as neighboring screens? If both computers have external monitors connected as an extended desktop, can you then create a larger extended desktop of all of tne monitors controlled from one computer?

What I'm trying to do is run all software from one computer, and use a series of monitors on both computers to display things.