"Related" characters from different sit-coms

Consider the statement:

“John Goodman is Debra Messing’s half-brother.”

This can only be true because Debbie Reynolds played Dan Conner’s mother in “Roseanne,” and she also played Grace Adler’s mother in “Will & Grace,” though she had a different husband.

So . . . each player will name a cross-sitcom relationship, and the next player will explain it, and name a new one.

Ok.

Valerie Mahaffey is John Mahoney’s daughter-in-law.

On “The Powers That Be,” VM was married to David Hyde Pierce, who played JM’s son on “Frasier”
Jean Smart is Jennifer Aniston’s mother.

Jean Smart plays Christina Applegate’s mother on “Samantha Who.” Applegate played Jennifer Anniston’s sister on “Friends.”

Jill Whelan is Valerie Bertinelli’s step-sister.