In my case it is a Sky and a normal Reciever. As is received on the Sky Reciever more and this is in the living room, I have this connected to the master, the others (bedroom) to the slave socket.
Now, when I look Sky, (also in HD) almost everything can be looked at what the other Reciever can normally receive in the bedroom. This is not a HD Receiver by the way.
But when I turn on the Sky Reciever eg ARD HD, the other Reciever is completely blocked because then comes to nothing! I turn on the Sky Reciever ARD one (no HD) then does the other but again.
So if I want to look at the normal HD programs in the living room is the bedroom Sense. The Sky programs (including HD) can be seen without the other Reciever is blocked!
Conclusion for me: I did what I mainly wanted to, I can on my Sky Watching football in HD, while over Grey's Anatomy can be seen, where SD (not HD) in my opinion is completely sufficient! :-)
Cheap solution to my problem, I'm satisfied.