Muffuletta Panini

Name: Muffuletta Panini
Ingredients: 1 cup chopped pitted pimiento stuffed green olives; 1/2 cup chopped pitted Kalamata olives; 2 tablespoons capers; 1/2 cup chopped roasted red bell peppers; 2 tablespoons chopped fresh parsley; 1/4 cup chopped celery leaves; 1/2 cup chopped celery; 1 teaspoon minced garlic; 1 tablespoon red wine vinegar; 2 tablespoons olive oil; Black pepper; For the panini:; 8 slices Italian bread; 4 tablespoons softened butter; 16 3/4 ounce slices Italian Blend cheese; 1/3 lb sliced mortadella; 1/3 lb sliced genoa salami; 1/3 lb sliced deli ham