A week ahead of the congressional hearing of four of the most powerful tech industry CEOs, the power struggle has already started.

Lawmakers and advocacy groups are jockeying to shape the logistics of the first-of-its-kind July 27 gathering where the CEOs of Amazon, Apple, Facebook and Google will face questions — likely virtually — from the House’s top antitrust panel. Seemingly small details, they say, could decide whether the hearing succeeds in pinning down the executives about their companies’ alleged misconduct.

The testimony is drawing attention just for the fact that the four chief executives — Jeff Bezos, Tim Cook, Mark Zuckerberg and Sundar Pichai, whose companies are worth a combined $4 trillion — are appearing together before lawmakers for the first time. It’s also the first congressional appearance ever for Bezos, the world’s richest man

The committee has yet to disclose crucial details about the hearing format, including whether the CEOs will testify simultaneously or how much time lawmakers will get to grill the moguls. In the interim, some lawmakers and advocacy groups are demanding big changes they hope will make it harder for the tech executives to skate by unscathed. And that task could be even harder given the additional logistical intricacies of what’s expected to be a largely virtual hearing.

“What we’re trying to fight for is a format in which the CEOs cannot hide behind each other or take advantage of the structure, to show up and get credit for showing up, but not actually provide the information that the subcommittee is seeking,” said big tech critic Sarah Miller, executive director of the American Economic Liberties Project.

Tech’s critics want the CEOs to testify separately

Miller’s organizations and tech antitrust advocates are calling for the House Judiciary Antitrust Subcommittee to make the tech CEOs testify individually. In a recent letter to the committee, they voiced concern that CEOs will be able to more easily dodge questions if they testify side-by-side on the same panel.

Separate, individualized testimony would also give lawmakers more opportunity to delve into the nuanced concerns over each company’s business model, said Miller. While Google has drawn antitrust scrutiny for its dominance in search and online advertising, for instance, Amazon’s role as massive e-commerce hub has drawn the attention of legislators and regulators alike. That makes the prospect of addressing them simultaneously a taller task than other past high-profile groups of CEOs on Capitol Hill, such as the famed 1994 grilling of seven tobacco industry chiefs.

“Even though these are all kind of classified as tech companies, it’s not the same as the tobacco industry. They’re very distinct corporations,” Miller said. She argued separate testimony will give lawmakers time to direct detailed questions at each CEO and get comprehensive answers.