Sparkling Citrus and Elderflower Rum Punch - The Local Palate

Ingredients

• 2 cups orange juice, plus more for ice float
• 2 cups pineapple juice, plus more for ice float
• 1 cup fresh lemon juice
• 2 cups white rum
• 1 cup St-Germain elderflower liqueur
• 1 ruby red grapefruit, thinly sliced
• 1 lemon, thinly sliced
• 1 bottle brut prosecco
• 2 (24-ounce) bottles Cannonborough Beverage Co. grapefruit-elderflower soda