DISSOLVE cherry gelatin in 3/4 cup boiling water in medium bowl. Stir in preserves. Coat 6-cup ring mold with no-stick cooking spray. Pour gelatin mixture into mold. Chill 30 minutes.
DISSOLVE lemon gelatin in 1 cup boiling water in medium bowl. Add sweetened condensed milk and sour cream. Beat with electric mixer on medium speed until blended. Pour over chilled berry layer. Chill 2 hours or until firm. Unmold onto serving platter.
COMBINE 1 cup raspberries and 1 cup blackberries. Fill center of mold. Garnish outside of dessert with remaining berries and mint leaves.