Heat oven to 350°F.
In bowl, combine crumbs, butter and juice. Stir to moisten; press into bottom and up sides of 9-inch pie plate. Bake in 350°F oven for 8 minutes. Remove to rack; let cool.
In bowl, combine egg whites and warm water; stir to dissolve.
In small saucepan, mix gelatin and 3 tablespoons of the sugar. In small bowl, combine yolks with milk. Stir into gelatin mixture. Over medium-low heat, cook, stirring frequently, until gelatin is dissolved and mixture registers 140°F on instant-read thermometer, about 8 minutes. (Do not boil.) Pour into large bowl; stir in juice. Refrigerate 15 minutes, stirring occasionally, until the consistency of unbeaten egg whites.
Beat dissolved egg whites until soft peaks form; gradually beat in remaining sugar until stiff peaks form.
With whisk, fold beaten egg whites into slightly thickened gelatin mixture until no white remains. Spoon into prepared crust. Refrigerate 3 hours.
To serve, spoon 2 tablespoons whipped topping onto each slice.