Why Mama Cass' Daughter Owen Was Not Part of Wilson Phillips: 'My Voice Was Too Loud' (Exclusive)

"They made quite a few really great records. It just wasn't the right combination," Owen Elliot-Kugell exclusively tells PEOPLE

• Mama Cass' daughter Owen Elliot-Kugell came up with the idea for Wilson Phillips, but was removed from the group

• She writes in her new book My Mama, Cass that she was "crushed and disappointed" to be ousted from the trio

• She tells PEOPLE she remains "really good friends" with Chynna Phillips, Carnie Wilson and Wendy Wilson

Mama Cass’ daughter Owen Elliot-Kugell is opening up about her experience with the pop group Wilson Phillips in her upcoming book and a new conversation with PEOPLE.

Elliot-Kugell, 57, exclusively tells PEOPLE that she's great friends with the women of Wilson Phillips — but in her book My Mama, Cass, reveals that the group was actually her idea, and being ousted before the trio's big break left her "crushed and disappointed."

While the My Mama, Cass author says she's “incredibly grateful” for Chynna Phillips, Wendy Wilson and Carnie Wilson, she writes that her time in the group ended after the other ladies determined her "voice was too loud" to blend properly with theirs.

“They made a great record. They made quite a few really great records,” Elliot-Kugell tells PEOPLE. “It just wasn't the right combination. It just wasn't the right combination.”

She continues: “It wasn't the right time and it was hard for me. Absolutely. That was hard for a while. And especially when they became such a big success. It definitely was a little bit bitter for me, I think — or bittersweet, I guess is the way to put it.”

In My Mama, Cass, Elliot-Kugell writes that after hearing "We Are the World," she was inspired to wrangle fellow children of '60s "hippies" to sing for a good cause. She took her idea to Phillips, whose parents John and Michelle Phillips were in the Mamas & the Papas with Elliot-Kugell's mom, Cass Elliot.

" 'Hey, I've got this cool idea,' I said. 'We've got all these friends whose parents were '60s musicians. Why don't we get together and write a song about drug abuse and record it for a charity?' " Elliot-Kugell writes.

Before long, the girls began calling "everyone we could think of," including Moon Zappa and Ione Skye. Eventually, they were able to successfully recruit Carnie and Wendy Wilson, daughters of The Beach Boys' Brian Wilson.

The foursome spent the next few months singing and rehearsing together, and eventually, Michelle Phillips took note and arranged for them to sing for producer Richard Perry. Perry liked what he heard, and before long, the group was recording demos.

Related: No, Mama Cass Did Not Die from a Ham Sandwich: In New Book, Her Daughter Shares What Really Happened (Exclusive) 

Unfortunately for Elliot-Kugell, a planned trip home to Massachusetts for the holidays put a wrench in her future with Wilson Phillips.

"I begged them not to record anything until I got back. When I returned, though, something didn't feel right when I spoke to the girls," she writes in her book. "What I didn't know was that in my absence it had been decided that I should not be in the group. The blend wasn't there — my voice was too loud."

She continues: "I was crushed and disappointed to have been edged out of something that I had helped create."

Wilson Phillips released their debut studio album in 1990, and the album sold over five million copies in the U.S. The record earned the group five Grammy Award nominations, and included hits like "Hold On" and "Release Me."

Looking back, Elliot-Kugell tells PEOPLE that her lack of involvement in the group “spurned [her] forward just a little bit more,” noting how she did “end up having a major deal with a record company and making a good part of one record before the label got bought by a Japanese company.”

“But I was glad to have that experience and it came full-circle,” she confesses. “The whole thing with the girls came full-circle when they asked me to come and sing on ‘Dedicated to the One I Love’ with them."

“Yeah, we're all really good friends,” she continues, adding that she’s “besties” with Carnie and Chynna.

Related: Mama Cass' Daughter Owen 'Didn't Even Know My Dad's Name' Until She Turned 19 (Exclusive)

Elliot-Kugell’s revelations about Wilson Phillips are just some of the many stories she discloses in her new memoir, My Mama, Cass, about her personal and professional life and her mother’s lifetime.

For more on Mama Cass, pick up the latest issue of PEOPLE, on newsstands Friday, or subscribe here.

My Mama, Cass is out Tuesday, May 7 from Hachette Books and is available for preorder now, wherever books are sold.

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Read the original article on People.