Process bell peppers, sugar, and 1 teaspoon salt in a blender, stopping once to scrape down sides. Pour into a small saucepan, and cook over medium heat 4 minutes or until thickened.
Combine ground beef and remaining 1/4 teaspoon salt; shape into 8 thin patties.
Combine cream cheese and jalapeño pepper; divide evenly in center of 4 patties. (Do not spread to edges.) Top with remaining patties; press edges to seal.
Grill, covered with grill lid, over medium-high heat (350° to 400°) 4 to 5 minutes on each side or until done. Serve on buns with bell pepper ketchup and desired toppings.