Not sure about the occurrence of five, though it was cute to see Roddy McDowall and Anne Francis from "Short Fuse" reunite in an episode of "Matlock" years later.

Another show with a lot of Columbo actors was "Burke's Law".

It starred Gene Barry and Gary Conway, with regular appearances by Michael Fox, so that's a good start right there.

Found one episode ("Who Killed Annie Foran?") that had Barry, Conway, John Cassavetes, Gena Rowlands, and Don Ameche.

Hi.

Yesterday I watched the TV movie "Fireball Forward" (1972), with at least eight names related to "Columbo": Ben Gazzara (director in the series), Ricardo Montalban, Anne Francis, Dana Elcar, L.Q. Jones, Eddie Albert, Kenneth Tobey and Don Eitner.

Regards