Subcontracted Alphabet Inc. workers in Missouri are petitioning the U.S. government to make the company collectively bargain with them, opening a new front in the struggle over what the internet giant owes workers it claims aren’t its employees.

In a filing Tuesday with the National Labor Relations Board, the Alphabet Workers Union requested the agency hold a unionization vote among about a dozen Google Fiber retail store staff in Kansas City, almost all of whom the union says it has signed up. AWU’s petition specifies that the workers are seeking to negotiate not only with the Alphabet vendor that officially employs them, BDS Solutions Group, but also with Alphabet itself, the parent of Google and its sibling unit known as Access that includes the high-speed internet service Google Fiber.

The workers contend that Alphabet is a "joint employer” — a company with enough control over a group of employees to be liable for their treatment and obligated to negotiate if they unionize, even if it doesn’t sign their paychecks.