Multiple DXC3200-M's in basement, how do I change channels independently?

I'm trying to do some planning for hosting March Madness in my basement.  I have 4 DCX3200-M boxes hooked up to 4 different tv's in my basement.  Unfortunately, right now when I use a remote to change the channel, it changes it on all of the boxes.  Is there any way for me to set the boxes up so that I can control each one independently?