Two kinds of Scotch and four kinds of citrus add up to a sophisticated cocktail, but the prep couldn't be easier. Mix a big batch and let guests pour their own.
In a large pitcher, combine all ingredients except orange twists. Set out pitcher with a long spoon for stirring the mix, a bowl of ice with tongs, glasses, and a bowl of orange twists.
*Make long, thin strips with a channel knife.
Make ahead: The mix, chilled airtight up to 1 day.