Preheat oven according to directions on pizzas.  Have all the ingredients place on table in containers.  Give each guest a pizza on a place and let them make it themselves.  Once they have garnished the pizza as they wish, place it in the oven for them and bake according to directions.  Four pizzas fit in the oven at once. 

While one group is making pizza, have another group make their salads.  This will cut down on the confusion and crowding.