Add chopped onions and bell peppers to a bag. Sprinkle in some cherry tomatoes and cover with Italian Dressing. Allow the whole thing to marinate in the fridge.
Get the BBQ going. Place the perforated grill pan on the BBQ and dump the whole bag into the grill pan. Cook and turn the vegetables.
When the veggies are going put the Italian Sausage on the grill, and cook them until done.