In a large bowl combine egg, bread crumbs, beer, caraway seeds, marjoram, garlic, salt, and pepper. Add veal; mix well. Shape meat mixture into four 3/4-inch-thick patties.
For a charcoal grill, grill patties on the rack of an uncovered grill directly over medium coals for 14 to 18 minutes or until done (160 degrees F), turning once halfway through grilling. (For a gas grill, preheat grill. Reduce heat to medium. Place patties on grill rack over heat. Cover; grill as directed.)
When burgers are nearly done, add rye bread slices to grill. Grill for 1 to 2 minutes or until bottoms are light brown. Turn slices over; top four slices with Swiss cheese. Grill for 1 to 2 minutes more or until bottoms are light brown.
Serve burgers on the cheese-topped bread slices. Spread the plain bread slices with mustard; top burgers.