What you are suggesting seems to be a VERY expensive complicated and intrusive way of doing things. Imagine miles of cable going from room to room and then back to one system.......I do not see the point. You will still have to go to the other room to change the CD or at the very least have a special remote capable of sending signals through walls plus you will need control boxes everywhere to switch on the speakers.....or face having to go to one room everytime you want to change the configuration of the speaker output.
I would buy a system for each room...much cheaper and far easier to control. Most modern audio appliances will have a usb input so a memory stick will do the job of storing Mp3 and plugging into each device.....save you the problem of having a Mac in the kitchen.

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