In a large bowl, combine bread and milk. Squeeze excess milk out of bread; discard milk. To the bread, add onion, mustard seed, seasoned salt, garlic, egg, salt and pepper; crumble beef and sausage over mixture and mix well. Shape into 1-1/2-in. balls.
In a large skillet, brown meatballs in oil; drain. In a large saucepan or Dutch oven, combine chili sauce, jelly and beef broth; slowly bring to a boil. Add meatballs; simmer for 30-45 minutes or until a thermometer reads 160°.