Meanwhile, puree the blueberries in a food processor. Strain through a fine sieve into a bowl and stir in the remaining 2 tablespoons of sugar, 1 tablespoon of tequila and 2 teaspoons of lemon juice. Carefully pour 2 tablespoons of the blueberry puree into each mold and cover with plastic wrap. Freeze until almost firm, about 25 minutes. Pour the remaining peach puree on top and freeze until almost firm, about 25 minutes. Finish with a blueberry layer and freeze until firm, about 1 hour. Unmold and serve.