How do you activate different redstone currents each time? [duplicate]

For a map I'm making, there's a "Palm Reader", represented by a villager. When you throw a diamond into a nearby hopper, it gives you a fortune. Is there a way to activate different /say command blocks each time, so its not just the same fortune over and over again?

I've done some research, and there doesn't seem to be anything on the topic.

You could use a loop which blocks all but one comparator at a time.

(I didn't have any command blocks, but you'll get the point)

(Scroll down for design (Paint markings))

In the circuit in the picture above you can see a loop with repeaters. Using the redstone all of the comparators but one are switched off, only allowing a current trough the one that is one.

When the user drops an item into the dispenser (use an item sorter to make sure it is a diamond), it will activate the command block which happens to be currenly accessible though the comparator.