Chop the bell pepper fine and sauté it in a skillet until tender.
Mix the ground beef and the sautéed bell pepper.
Cook on a grill or skillet until well browned on both sides. (I prepared my burgers on an inside grill. I also grilled my pineapple)
Stir together the soup, reserved pineapple juice, brown sugar, and vinegar in a large skillet.
Heat this soup mixture to a boil.
Add the burgers
Cover and cook for 5 minutes or until the burgers are cooked through.
Add a piece of swiss cheese to the burger and allow it to melt.
Add your favorite BBQ sauce to each hamburger bun.
Serve the burgers and a slice of pineapple on each Hawaiian hamburger bun.