I was working on the circuits in my house, and found a bundle of nine identical wires, going into the wall and up to the attic. In the attic were the nine wires going down to the main floor. Suppose I can twist any number of wires together at either end, and I have a circuit tester that lights when a loop is complete.

How can I match up all nine pairs of wire ends, using the smallest number of trips up to (and down from) the attic?

Assume the wires are insulated except for a few bare cm at the ends. Wires cannot be pulled thru the wall or pipe.