Corin Redgrave & Lynn Redgrave
Brother & Sister
John Forsythe & Christopher Cazenove
They played brothers on 'Dynast' and died one week apart.
Tony Curtis, Dorothy Provine, Blake Edwards
Tony and Dorothy starred in "The Great Race" which Edwards directed.
Peter Graves, Barbara Billingsley, Leslie Nielsen
They all starred in "Airplane!"
Harold Gould and Tom Bosley
Both of them played Howard Cunningham of 'Happy Days' - Gould in the 'Love, American Style' pilot and Bosley in the series
Tom Bosley & Ralph McInerny
Bosley played Father Dowling in 'The Father Dowling Mysteries' which McInerny wrote.
Freeman co-starred in 'You'll Never Get Rich' (the 'Bilko' show) and Barry Blitzer wrote for 'The Phil Silvers Show'
Simon MacCorkindale & Chao-Li Chi
Both appeared in 'Falcon Crest' and died only days apart.
Buff Cobb & Frances Buss Busch
Ms. Cobb hosted 'Mike and Buff' which Ms. Busch directed.
James Wall & Stuart Hample
Both appeared on 'Captain Kangaroo'
There may have been other such connections, but as I said, those were the ones that jumped out at me.