Make Room For Granddaddy to The Bold and the Beautiful

Make Room for Grandaddy's Williams had Here's Lucy's Lucy Carter as a houseguest

Here's Lucy's Lucy Carter and Mannix's Mannix are held hostage in an episode of Here's Lucy.

Mannix returned to TV on an episode of Diagnosis Murder to solve an old unsolved case with the help of Dr Mark Sloan.

Diagnosis Murder's Dr Mark Sloan was defended by Matlock when Sloan was accused of murder

Both have characters that have flown on the fictional Trans Global Airlines

The Young and the Restless and The Bold and the Beautiful crossed over multiple times.