The link is Charles Albertine, who wrote "Bandstand Boogie" for Larry Elgart and produced a number of Three Suns albums (their best ones, imo) as well as Nevins' solo work "Dancing with the Blues."

Albertine and Nevins also collaborated on this bit of exotica: https://youtu.be/57P17PlAo-E

There's another connection: Albertine was a contract writer for Aldon Music and contributed to the theme song for the soap opera Days of Our Lives, along with Brill Building artists Boyce and Hart. I don't know if he ever actually worked out of 1650.