On cutting board, place 4 bread slices; spread each with 1/2 teaspoon mustard. Divide ham, cheese, and pickles onto bread. Spread 1/2 teaspoon mustard on one side of each of 4 more bread slices. Place bread, mustard side up, on sandwiches; divide turkey and tomatoes onto bread. Spread one side of remaining bread with remaining mustard and place, mustard side down, on top of sandwiches.