- '2 cups fresh pink grapefruit juice (from 2-3 grapefruits)'
- '1/2 cup St-Germain (elderflower liqueur)'
- '1/4 cup Campari'
- '1 750-milliliter bottle chilled sparkling wine'
- Combine grapefruit juice, St-Germain, and Campari in a large pitcher
- Cover and chill until cold, about 2 hours
- Divide grapefruit mixture among glasses and top off with sparkling wine
- DO AHEAD: Grapefruit mixture can be made 1 day ahead
- Keep chilled