Combine 4 cups water and sugar in a large saucepan; bring to a boil.
Cook until sugar dissolves, stirring occasionally.
Pour over tea bags.
Cover and let stand 5 minutes; discard tea bags.
Stir in juice, vodka, and Grand Marnier; chill.
Gently stir in gingerale.
Serve over ice; garnish with rind, if desired.