To make the marinade, combine the 3/4 cup olive oil with the pepper, marjoram, rosemary, onion and garlic.  Add the lamb to a re-sealable platic bag or container.  Add the chicken to a re-sealable plastic bag or container.  Divide the marinade between the lamb and chicken, close and refrigerate for 2 hours and up to overnight.

Preheat the grill to medium high.  Brush the pita bread with a little olive oil and set aside.

In a mixing bowl, mix the yogurt, cucumbers, and lemon juice together. Season with salt and pepper and set aside.

Remove the lamb and chicken from the marinade and place on the grill and cook for 2 to 3 minutes on each side. Place the pita bread on the grill and cook for 2 minutes on each side.

Spread the cucumber sauce evenly over each pita bread. Divide the lamb slices between the three pita breads. Divide the chicken up between the remaining pita breads. Garnish each sandwich with lettuce, onion, and tomato. Place the pita bread on parchment paper. Roll the sandwich up tightly in the parchment paper, tucking the ends into the sandwich. With a serrated knife, slice the sandwiches in half and serve.