Preheat oven to 375°.
Combine first 7 ingredients in a large saucepan; bring to a boil. Add zucchini, squash, and bell pepper; reduce heat, and simmer 4 minutes. Add mushrooms; simmer 2 minutes. Drain well; discard liquid and peppercorns.
Place pizza crust on a baking sheet. Sprinkle with half of feta; top with vegetable mixture. Sprinkle with remaining feta and parsley. Bake at 375° for 10 minutes or until thoroughly heated (cheese will not melt). Drizzle with olive oil.