The general issue here is that you need a more advanced structure than a simple hash because a simple hash can only have one value for each key. Perl data structures from perldoc may be helpful to you in understanding the code other monks have posted. You need a "Hash of array of Hashes". The code that other Monks have posted does work, but to understand why it works, read the link as a starting place.

update: My latest motto (modern version of "give a man a fish"):
Give a man a gun and he can rob a bank. Teach a man to be a banker and he can rob the world.

Not meant as a overt political statement although it is intended to be humorous. It is important to understand why the code works so that you can extend it and use it in other situations.