Pat steaks dry with paper towels. Rub both sides with salt and pepper. Cut steaks crosswise in half. Let stand at room temperature for 20 minutes.

Stir together melted butter and garlic powder; set aside. Prepare a charcoal or gas grill for direct cooking over medium-high heat (375 to 400°).

Using kitchen shears, cut through the top of the lobster tails and down the center just to the tails. Split the shells. Use thumbs and finers to spread shells open. Gently loosen lobster meat from shells; pull meat away from bottom sells, leaving tail portions attached. Close shells and carefully place row of meat on top.

To assemble packets, cut four 18x12-inch sheets of heavy foil. Fold sheets in half; then open. Place potatoes evenly in the center of one-half of each sheet of foil; spread to a single layer. Arrange asparagus on half of the potatoes near folded edge. Place lobster on top of asparagus; top each lobster tail with 1 teaspoon butter mixture. Place steak pieces on other half of potatoes next to lobster tails. Fold other half of fold up and over lobster and steak; double-fold to seal.

Grill packets for 8 to 12 minutes or until lobster is opaque (145°) and steaks reach 130° for medium-rare doneness. Brush lobster and steaks with melted garlic butter before serving. Garnish with chopped parsley, if desired.