Combine sugar, flour, salt, and water in heavy saucepan; stir well. Stir in fruit rind and juices. Cook over medium heat, stirring constantly, until mixture thickens and boils. Gradually stir about one fourth of hot mix into egg yolks; add to remaining hot mix, stirring constantly. Return to a boil; cook 1-2 minutes, stirring constantly. Remove from heat, and let cool completely. (Mix will be thick)
