Elecktra Records decided to hold auditions for a “supergroup” in 1967. Here’s the details from the Wikipedia article on Rhinoceros:

“Paul A. Rothchild, then Elektra Records’ talent scout and house producer, and fellow producer Frazier Mohawk (formerly Barry Friedman), decided to individually sign talented young musicians and form them together into a group in this fashion. While Mohawk had been instrumental in coordinating band membership for what became Buffalo Springfield (encouraging Stills to form Buffalo Springfield following his Monkees audition), the establishment of what became Rhinoceros involved a more formal third party role.

Rothchild and Mohawk initially invited twelve musicians to audition in September 1967, at Mohawk’s house in Laurel Canyon. Included in this initial group were Doug Hastings (guitar) and Alan Gerber (keyboards and vocals). A second audition was held at a Los Angeles motel in November 1967, where approximately twenty musicians were reviewed. After this meeting, John Finley (vocals) and Danny Weis (guitar) were chosen to work with Hastings and Gerber. Finley and Hodgson were both former members of Jon and Lee & the Checkmates, a band which Rothchild had expressed an interest in signing as early as 1965 that had broken up in September 1967.

Weis had been an original member of Iron Butterfly and played on their debut album. Hastings had been a member of Seattle’s Daily Flash, and briefly served as Neil Young’s replacement in Buffalo Springfield, during one of Young’s departures from the group. Other members of the Daily Flash were invited to audition for Rhinoceros, though only Hastings was chosen.

Weis then suggested former Iron Butterfly bandmate Jerry Penrod as the bass player for Rhinoceros; his suggestion was accepted. Former Checkmate keyboard player Michael Fonfara was then invited to join the lineup. Fonfara had joined The Electric Flag in mid-November 1967, for sessions and a brief tour of the northeast U.S. and California. During mid-December, he ran into Finley and Hodgson at the Tropicana Motel in Los Angeles, and was encouraged by Finley to sign on to the Rhinoceros project. Based on Finley’s recommendation, Fonfara was brought into Rhinoceros, following the completion of his obligations to the Electric Flag. John Keleihor, former drummer for The Daily Flash, contributed to some of the group’s early recordings, but departed early on. The final member chosen, in early 1968, was Billy Mundi, former drummer for the Mothers of Invention.”

Their first album was not the hoped for smash but contained some great music:

“Apricot Brandy” was the charting single from the group, it would peak at #46 and spend 10 weeks on the Hot 100. Another single from that from LP that failed to chart was “You’re My Girl (I Don’t Want To Discuss It)”, the B side, which made the chart on WPTR in Albany, New York, was “I Will Serenade You”, written by band member John Finley. Five years later Three Dog Night” would reinvent the song and reach #17 on the Hot 100

I 1969 they released the “Satin Chickens” LP and “Back Door” was the single that failed to chart. Their final album was “Better Times Are Coming”, they released two final singles, again failing to chart. Listening to their music 50 years later, it was much better than the public recognized and it’s stood the test of time. I’ll close this post with the first single off the last LP “Better Times”

For more on the continuing history of Rhinoceros, here’s the link to the band’s website: Rhinoceros: The Band