Halve and pit 2 plums, 2 apricots and 2 peaches. Grill over medium-high heat, turning occasionally, until slightly charred, about 4 minutes. Transfer to a cutting board and cut into large pieces. Transfer the fruit to a pitcher and add one 750-ml bottle rose, 1/2 cup coconut rum and 1/4 cup superfine sugar. Refrigerate overnight.