DO FILLING. Mix sugar and cornstarch in a saucepan. In a bowl, combine condensed milk and water. Gradually add milk mixture to the cornstarch mixture. Cook on low heat until thickened, about 8-10 minutes. Turn off heat.
ADD egg yolks to the thickened cornstarch-sugar mixture, beating vigorously to avoid cooking the eggs. Return pan to low heat and cook for 2 minutes more. Cool.
ASSEMBLE. Arrange 6 Grahams (dipped in the fruit cocktail syrup) on the bottom of an 8-inch square pan. Spread half of the custard evenly on top of the crackers. Top with ½ cup of fruit cocktail. Repeat procedure.
BREAK agar-agar in ½ cup of cold water to soften. Boil another ½ cup water, add the softened gulaman mixture and 1 tablespoon sugar. Boil until gulaman is completely dissolved. Pour gulaman on top of fruit cocktail. Chill and serve.