Guess the common thread. Answer below. During the Grammys award show on TV a few nights ago, I posted this comment over on Facebook. Speaking of music - in 1970 and 1971 these two albums won best album of the year. Collectively over that two year span - they "beat out" (subjectively needless to say) these other artist also having albums nominated in that category: The Beatles Abbey Road, the 5th Dimension, CSN (eponymous debut), Johnny Cash, Chicago I (their debut DSA - double studio album), the Carpenters, CSN's (again) Deja Vu, Elton's eponymous debut LP, and Sweet Baby James by James Taylor.
These two records connected by: producer Roy Halee.