Preheat a grill over high heat or start a campfire. Cut four sheets of foil about 12-inches (30cm) long.
Divide the peppers and onions between the foil sheets. Drizzle with the chicken broth or wine, then sprinkle with the herb seasoning. Season to taste with salt and pepper.
Grill the sausages until charred, about 3 minutes per side, then divide them among the foil packets.
Fold the foil packets crosswise over the sausage mixture to completely cover the food. Roll the top and bottom edges to seal them closed.
Place the foil packets on the grill or in the campfire and cook until the peppers and onions are tender, 15 to 20 minutes, flipping halfway through.
Carefully open each foil packet and serve immediately.