Mix ground beef and Sauce Mix-Ins until well blended. Shape into 4 patties.
Grill over medium heat 4 to 6 minutes per side or until burgers are cooked through (internal temperature of 160°F). Grill onions and bell peppers in grill basket or grill rack 3 to 4 minutes or until tender and lightly browned, stirring frequently. Toast rolls on the grill, open-side down, about 30 seconds or until golden.
Serve burgers on toasted rolls topped with lettuce and grilled onion and bell pepper mixture.