Prep charcoal grill with medium-hot coals or heat gas grill to medium-high heat.
Using 12-inch-wide heavy-duty aluminum foil, cut 4 pieces 32 inches long; fold each piece in half to make a 16 x 12-inch rectangle. Generously coat foil pieces with nonstick cooking spray.
In large bowl, stir oil, rosemary, lemon juice, and 1/2 teaspoon of the pepper. Brush onto both sides of pork; toss remaining mixture with tomato, squash, zucchini, artichokes and capers.
Evenly place mixture on one half of each foil piece. Season pork with salt and remaining 1/8 teaspoon pepper. Top vegetables with pork.
Fold second half of foil over pork and vegetables. Tightly seal sides and front edges, leaving space for steam to build. Place packets on grill rack. Grill 20 minutes; 5 minutes before packets are finished, slice bread and grill on both sides. Carefully open packets; transfer contents to 4 serving plates. Serve with grilled bread.