Mouse without borders does exactly what I want and it's free. By disabling "Easy Mouse" I can just swap between the two PC's and use the mouse on them separately. The only issue it has is that if I am in a full screen application (Video game), it will minimize the video game while I am moving the mouse on the second monitor. If somehow Multiplicity has solved this problem hidden in some random settings then you have my money.
Megatf
Also the reason why this is a huge deal breaker is because if I am trying to FPS game in seamless mode, if I turn my character in left or right directions using the mouse and keyboard I drag my mouse off the primary display and onto secondary displays which stops all input on the primary PC.
Alright, hopefully you made it past my awkward title. So, seamless mode is cool but I have two monitors connected to my Secondary PC to either side of my Primary PC monitor. What I am looking to do is press a hot key to simply switch control of the Mouse and Keyboard to the secondary PC without changing the Primary Monitors display. I am a gamer and a streamer. I stream from my primary PC into my secondary streaming PC to do all the GPU/CPU intensive encoding and o