Stir cilantro, parsley, and mint together in a small saucepan. Remove half of the herb mixture, and set aside. Stir the garlic, lemon, olives, olive oil, and black pepper into the remaining herbs. Spread 2 tablespoons of this mixture onto the lamb rack. Wrap the exposed bones with aluminum foil to keep them from burning. Stir the olives and bell pepper into the reserved mixture and keep warm over low heat.