(or one of each) In a large saucepan, combine cream cheese, soup, and onion. Heat until all dissolved and blended. Add mayonaise, mix well, and remove from heat. Sprinkle gelatin over water and heat until dissolved. Add celery and seafood to soup mixture, then add gelatin and mix all well. Pour into 6-cup mold and chill until set. Serve with sourdough rolls thinly sliced and crackers.