Place a sheet of cheesecloth on top of each foil sheet. Add clams, dividing evenly. Top with sausages, potatoes, garlic, and corn, dividing evenly. Sprinkle with Old Bay seasoning. Fold edges of foil up into a bowl shape around the clam mixture and pour 1/2 bottle of beer into each packet. Drizzle lightly with olive oil. Fold foil into tent-style packets and seal edges tightly.
Place packets on preheated grill and cook for 20 to 25 minutes or until potatoes are tender and clams have opened. Open packets and discard any clams that have not opened. Drizzle clam mixture with melted butter and garnish with parsley.
You can substitute 1-1/2 cups of vegetable or seafood broth for the beer.