In small bowl, soften gelatin in cold water. In top of double boiler, beat egg yolks; blend in milk. Cook, stirring constantly, over hot water until mixture thickens slightly. Add softened gelatin and coffee; stir until dissolved. Remove from heat. Stir in vanilla and 3 packets Sweet 'N Low. Chill until mixture is consistency of unbeaten egg whites. In a large bowl, beat egg whites with electric mixture until foamy. Add remaining Sweet 'N Low. Beat until stiff. Fold chilled custard mixture into egg whites. Pour into serving dishes. Chill until set.