Place the guavas in a large pot and fill with enough water to cover, about 2 quarts. Bring to a boil, then simmer over medium heat for about 30 minutes. Drain fruit and pass through a strainer or food mill to turn into pulp.
Place the pulp in a stainless steel or copper pot and stir in 4 cups of sugar and orange juice. Cook over medium heat, stirring constantly with a wooden spoon, until the mixture is thick enough to peel off of the bottom of the pan.
Cover the surface of a 10x15 inch jellyroll pan with about half of the remaining sugar. Pour the hot guava mixture onto it and sprinkle the remaining sugar over the top. Let it cool to room temperature. When cooled, cut into squares and wrap in dried plantain leaves if you like. You could wrap in waxed paper or cellophane if the leaves are not available.