Preheat the oven broiler. Line a baking sheet with aluminum foil.
Open the sandwich roll onto the prepared baking sheet. Spread the mustard-mayonnaise blend on one half of the roll and top with the turkey, Swiss cheese, and ham.
Spread 1 tablespoon of mayonnaise on the other half of the roll and top with the roast beef, tomato slices, and Muenster cheese.
Broil the sandwich open-faced until the cheese melts and begins to bubble and the ham begins to crisp around the edges. Remove the sandwich from the oven and put both sides together.
