1 pound granulated sugar
6 cups water
1-1/4 ounces lime juice concentrate
8-1/2 ounces lemonade concentrate
3/4 cup crème de menthe (a non-alcohol syrup available at liquor stores. Note: This is not the same as crème de menthe liqueur.)
Combine the sugar and water in a large saucepan; set on low to medium heat. Stir until sugar dissolves. Add in lime and lemonade concentrates. Raise heat to medium and continue stirring. Bring to just below the boiling point (210 degrees) but do not allow to boil. Remove from heat; add crème de menthe and chill. Once chilled, add a ratio of 1 part sugar syrup to 5 parts water. Transfer beverage to a pitcher and serve.