Bring the sugar and 1/2 cup water to a boil in a small saucepan, stirring until the sugar has dissolved. Remove the pan from the heat, and stir in the rosewater. Let cool, then transfer the syrup to a 3-quart pitcher.
Add the wine, soda water and grapefruit soda to the pitcher, and stir to combine. Add the raspberries, and cover the pitcher with plastic wrap. Refrigerate the sangria to chill, at least 4 hours up to overnight.
To serve, fill 8 glasses halfway with ice, then pour the sangria and fruit into each glass.
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