The night before, arrange lime wheels in a bundt pan or ring mold, cover with 2 cups water, and freeze solid: this is the ice ring that keeps the punch cold without diluting it.

In a large pitcher or dispenser, combine the pineapple juice, orange juice and mango nectar, stirring until the color is even throughout.

Stir in the fresh lime juice; the mixture should taste bright rather than flat, with the lime cutting through the sweetness.

Refrigerate the base until ready to serve, up to 24 hours ahead.

Just before guests arrive, add the ginger ale and stir once, gently, to keep the fizz.

Unmold the ice ring and float it on top, then garnish each poured glass with a fresh lime wheel and a small sprig of mint.