SAN FRANCISCO — A federal judge on Friday struck down an effort to form a class-action lawsuit to go after Apple, Google and five other technology companies for allegedly forming an illegal cartel to tamp down workers’ wages and prevent the loss of their best engineers during a multiyear conspiracy broken up by government regulators.

U.S. District Judge Lucy Koh in San Jose, Calif., issued a ruling Friday concluding that the companies’ alleged collusion may have affected workers in too many different ways to justify lumping the individual claims together. She denied the request to certify workers’ lawsuits as a class action and collectively seek damages on behalf of tens of thousands of employees.

The allegations will be more difficult to pursue if they can’t be united in a single lawsuit. Koh, though, will allow the workers’ lawyers to submit additional evidence that they have been collecting to persuade her the lawsuit still merits class certification.

“Plaintiffs appreciate the court’s thorough consideration of the evidence and are prepared to address the court’s concerns fully in a renewed motion,” employee attorney Kelly Dermody wrote in a Friday email.

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The companies targeted in the lawsuit have been vigorously fighting the allegations. More is at stake than potentially paying out significant damages to more than 100,000 workers. If the lawsuit proceeds, it could also expose secret discussions among prominent technology executives who entered into a “gentlemen’s agreement” not to poach employees working at their respective companies.