This section takes a look at the various crossovers with related shows The Golden Girls and Nurses.
Empty Nest characters on The Golden
Girls
Richard Mulligan appeared in three
episodes. In "Yokel Hero," Harry stops by the girls' house to drop off their
mail. In "Sick and Tired, Part 2," Dorothy visits Harry at the hospital when she
is trying to figure out the cause of her illness. And in "Not Another Monday,"
the girls consult Harry when the child they are babysitting gets sick.
Kristy McNichol appeared in two episodes. In "Witness,"
Sophia reports her missing glasses to the police station and Barbara stops by
the check out the claim. She later returns with Sophia's glasses; Dreyfuss was
the culprit all along. In "A Midwinter Night's Dream," Barbara shows up to
confront Sophia, who attempted to cause a fight between Barbara and Carol to
break a Sicilian curse. 
Dinah Manoff appeared in two episodes. In "The Monkey Show," Carol is on a date with Stan's psychiatrist Dr. Halpern when he is called to the girls' house to help Stan with a problem. In "A Midwinter Night's Dream," Carol invites herself over to Blanche's full moon madness party.
David Leisure appeared in one episode. In "Questions and Answers," Dorothy dreams that she is a contestant on Jeopardy against Rose and Charley. Note: David Leisure also appeared in the episode "Empty Nest," the show's original pilot, as Oliver.
Park Overall appeared in the episode "Sick and Tired, Part 2," when Dorothy visited Harry at the hospital.
The Golden Girls characters on Empty
Nest
Beatrice Arthur appeared in one episode.
In "Dumped," Barbara dates Dorothy's nephew and is heartbroken when he dumps
her.
Betty White appeared in three episodes. In "Strange
Bedfellows," Rose returns a batch of flyers to Harry after Carol had placed them
around the neighborhood. In "Rambo of Neiman Marcus," Rose takes Harry's car in
for repairs after she accidentally hits it. In "Dr. Weston and Mr. Hyde," Rose
stops by for some advice about romance. 
Rue McClanahan appeared in one episode. In "Fatal Attraction," man-hungry Blanche thinks she is in love with Harry and will not take no for an answer.
Estelle Getty appeared in two episodes before becoming a series regular. In "Libby's Gift" she stops by Harry's house to complain about the noise he is making playing the organ. In "Windy," she stops by the warn him of the coming hurricane.
Empty Nest characters on
Nurses
Note: Since I do not have access to
episodes of Nurses, this list may be incomplete.
Richard
Mulligan appeared in the episode "The Eagle Has Landed."
Dinah Manoff appeared in the episodes "Playing Doctor" and "Temporary Setbacks."
David Leisure appeared in the episode "Moon Over Miami."
Park Overall appeared in the episodes "Begone with the Wind" and "In My New Country."
Estelle Getty appeared in the episode "Temporary Setbacks."
Nurses characters on Empty
Nest
David Rasche appears in the episode
"Love and Marriage," in which Jack Trenton and Charley (who is doing community
service at the hospital) attempt to see who can do less work.
Loni Anderson appears in the episodes "Bye Bye Baby...Hello, Part 1," "Mama Todd, the Sequel,"and "Mother Dearest."