At first, I was faced with the choice to make every single socket switchable.
However, by experience from other KNX users, i came to the conclusion that this would be unnecessary waste of money. But I did not want to do completely without it.
My compromise consisted to connect each individual socket with a 3-wires cable and any double or multi-lead socket with a 5-wires cable to the central distribution box. Inside the distribution box, these cables are normally connected on the individual fuses. By using 5-wires cables at the double sockets you can decide to make it switchable afterwards.
There are currently 3 sockets, which I made switchable in this way. 2 sockets for the bedside lamps and 1 sockets for my subwoofer which is in a difficult reached position.