In a blender container, combine gelatin, water, and lemon juice.
Cover and blend at medium speed until gelatin dissolves, about 45 seconds.
Separate pieces of frozen fruit by rapping the package sharply against counter edge.
Place half of the fruit in blender with gelatin mixture.
Blend at medium speed for 1 seconds.
Add remaining fruit; blend just until smooth.
Beat egg whites until stiff peaks form.
Fold fruit into egg whites.
Spoon into serving dishes; chill for 3 hours.
Serve with Custard Sauce.