Peel onions and cut in half crosswise. Remove centers of onions leaving about 1/2" shell. Chop up centers into pork. Add dill, salt, pepper and rice, green pepper, egg and about 2/3 c. of the soup. Mix well.
Divide mixture into 8 portions and fill onion shells rounding off the tops. Place in a roasting pan. Pour 1/4 c. boiling water into pan and cover tightly. Bake at 350 degrees for 50 minutes. Baste onions with the liquid and bake uncovered for 10 minutes.
Pour off 1/2 cup pan juices into a small sauce pan. Stir in flour. Add milk to remaining soup can, stiring to mix. Add to pan liquid and cook until thick. Pour over onions to serve.