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.
Create a packet; 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.
Note: Packets can be baked at 450° for 20 minutes.