Combine the mint and the lime juice in a small pitcher. Use a muddler to crush the mint in the lime juice, this should take a minute or two. Add the simple syrup and rum to the pitcher. Fill the pitcher about 2/3 of the way to the top with ice and stir well to mix and chill. Fill individual glasses halfway with ice, then 2/3 of the way full with the mojito mixture, then top each glass with club soda. Enjoy!.