Cook pasta according to package directions; drain and rinse in cold water. Place in a large bowl and set aside.
Meanwhile, cut the eggplant, zucchini and summer squash lengthwise into 3/4-in.-thick slices. Brush the eggplant, zucchini, summer squash, red onion and red pepper with oil; sprinkle with salt and pepper. Grill vegetables, covered, over medium heat for 4-6 minutes on each side or until crisp-tender. When cool enough to handle, cut into cubes.
Add the tomatoes, feta cheese, olives, parsley and grilled vegetables to the pasta. In a small bowl, whisk the vinaigrette ingredients. Pour over salad; toss to coat. Cover and refrigerate until serving. Yield: 26 servings (3/4 cup each).