Pour the pomegranate juice into an ice cube tray and freeze overnight. Put the lemon juice and sugar in a small saucepan and bring to a simmer; cook, stirring, until sugar is completely dissolved. Cool to room temperature.
To serve, fill a tall rocks glass with 3 to 4 pomegranate ice cubes. Pour about 1/4 cup of the lemon syrup over the ice and top off with seltzer. Repeat with the remaining ingredients. Stir gently, garnish each glass with a lemon wheel and serve.
Cook's Note: This recipe is easily doubled or tripled for a crowd