Parental controls and multiple TVs

I wanted to block a particular channel for my stepson, so I did that on his TV.  Went to another room, could still see the channel, so I went around to all rooms to block it.  Then, on his TV, I blocked some ratings.  Went to another TV... and the ratings were blocked!  So I had to undo that.

How do I control what happens on just one receiver vs. the whole system?