To control two conscious beings, would be like trying to control some person in real life... Each consciousness is going to have with it, its own will and disires. You can only have control over one consciousness at a time, it only makes logical sense.

Usually our mind is made up of millions of wills and disires and programming, that all mixes and balances to make one consciousness. For instance when you talk to dream characters, they seem to have their own consciousness wills and disires, but in essence you can see that they don't when your able to control what they do, even what they want.

Consciousness is a very unique and pretty undefined thing... It's really hard to debate whether or not it can be split. But I think of consciousness like a focal point, a dot in an ocean of subconscious currents. They all focus onto one point. Mathematically, a point is defined as infintesimal, you can't divid it in half. If consciousness were a tangable object or function, we could break it down into parts and perhaps copy and divid it... but it doesn't really have those properities.

I'd be pretty scary if someone could copy their consciousness and spread it around. It would be screwed up.
but thats just me.

-Daniel