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. Cool. Stir in juice, vodka, and Grand Marnier; chill.
Gently stir in ginger ale. Serve over ice; garnish with rind, if desired.
This is a fine make-ahead recipe for an open house. Combine the ingredients through step one and chill; stir in the ginger ale just before serving. Serve in goblets, highball glasses, or any pretty clear glasses to show off the concoction's yuletide-red hue.