OK, here goes:
First you do a 2:4 demux using two SPDT switches. One switch connected to L, the other to N. Four lamps are connected between the four outputs from the switches in the four combinations possible. Now you can light each bulb independently.
In the second stage you add the third switch that controls two DPDT relays between the first two switches and the lamps. Add a second group of four lamps. The relays switch between the two groups of lamps. Now you have a 3:8 demux. Remove one lamp of your choice, and you can control all seven lamps individually, plus turn them all off.