ride on one's coattails
ride on one's coattails {v. phr.}
To succeed in a certain endeavor by attaching oneself to the greater weight of another person or corporate body.
"We will never get our Ph.D. program approved on our own," said the head of the modern dance department, "but we might succeed if we stay in the Division of Fine Arts, riding on their coattails, as it were."
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Source: A Dictionary of American Idioms