In a medium bowl, combine the berries and sugar. Gently stir together. Set aside in the fridge for 15 minutes.
In a pitcher, add the berries, mandarin slices and rosé wine. Cover with a lid. Chill in the fridge for at least 4 hours and up to 24 hours.
Right before serving, add Framboise Lambic. Stir to mix and taste. If needed, add a little more sugar. Serve with or without ice.