Took me a little while, and I'm certain there's a shorter route, but here goes:
Albert and Steiger in Oaklahoma
Steiger and Poiter in In the Heat of the Night
Poitier and Dan Akroyd in Sneakers
Ackroyd and Hanks in Dragnet
Hanks and Ryan, well, they don't make romance movies without Hanks and Ryan anymore.