Help for Rolling Dice the Shadowrun Way

In Shadowrun, you typically get to roll a number of six-sided dice. You are given a 'target number' which you are supposed to beat. When rolling the dice, you pick out all the dice with a '6' showing and roll them again, adding the second roll to the total result for that die. You keep doing this until the die no longer rolls a '6'. After all this is done, you count how many of the dice whose total equalled your target number or more. This number is your number of Successes.