1. Purée pineapple in a blender or food processor.
2. Crush mint with a mortar and pestle or coarsely chop. Divide mint among 8 large glasses or canning jars. Add 1/4 cup pineapple purée and 2 tablespoons each Lemon Grass Syrup, lime juice, and rum to each glass. Fill glasses 3/4 full with club soda. Stir in about 1/3 cup cracked ice. Serve immediately.