in reply to Reconciling multiple lists (similar to "merge" in CVS?)
This may be a long winded way of doing it, but what about this?
1.Dump all your arrays in to a hash to get frequency of the letters
2. Rebuild array comparing original array element and hash key, and checking if value is < 1 then that element is undef.
Unless I've misunderstood what you want, doesn't that do what you're after?
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