Wash and peel the guavas. Blend them with the water until you get a thick juice without lumps, pass it trough a strainer to remove the seeds. Sweeten with Le Zuc. In another bowl, hydrate the Jell-O with the warm water and add it to the guava concentrate. Finally add the yogurt, mixing with an electric mixer. Serve the mix in individual jars and refrigerate for approximately 4 hours. Serve with yogurt.