Set up grill for direct cooking over medium heat. Oil grate when ready to start cooking.
For the dough:
In a large mixing bowl, combine pizza crust mixes, Italian seasoning, and hot water. Stir about 20 times until a ball forms. Split ball in half and cover each with plastic wrap; set aside.
For the filling:
In a large frying pan over medium-high heat, add the oil and cook ground beef and sausage, stirring frequently to break up clumps. Cook until no longer pink but not totally cooked through, about 4 minutes. Remove from heat and stir in mushrooms, olives, cheese and 1 cup of the marinara sauce; set aside.
Unwrap dough and put onto 2 parchment lined baking sheets sprinkled with cornmeal. Press out into 2 (12-inch) circles about 1/4-thick; pinch together any holes. Spoon the meat mixture into center of each dough round. Slide the second dough circle off the parchment to top the meat mixture. Crimp the edges together. Gently pat entire surface of pizza until flat. Slide pizza onto hot oiled grill. Cook, covered, for about 5 to 6 minutes per side.
Warm the remaining marinara sauce in the microwave. Spoon some sauce on the plate and serve a hot slice of pizza on top.
INDOOR: Preheat oven to 425 degrees F. Lightly spray baking sheet with cooking spray; set aside. Prepare stuffed pizza as directed. Place on prepared baking sheet and bake in preheated oven for 20 to 25 minutes or until golden brown.