For the filling: Place the garlic, green onions, pine nuts, jalapeño pepper and cilantro in a food processor fitted with the steel blade. Process to form a thick paste. With the machine running, pour the olive oil in a thin, steady stream through the feed tube until all is incorporated. Remove to a small bowl and stir in olives, salt and pepper.
If the pork roast is tied, untie it and roll it out flat. Spread two-thirds of the garlic-cilantro paste over the meat. Reroll the roast and tie it.
Stir the grapefruit, orange and lime juices into the remaining garlic-coriander paste. Make shallow incisions over the surface of the roast with the tip of a sharp knife. Place the roast in a shallow dish or pan and pour mixture over to marinate. Let marinate in refrigerator, turning occasionally, for 24 hours.
To cook the roast: Preheat oven to 375 degrees. Remove roast from the marinade and place it in a roasting pan. Roast uncovered, basting occasionally with any leftover marinade, for 1¼ hours. Discard marinade. Brush the roast all over with the hot pepper jelly and roast 15 minutes more or until done.