How can I launch Chrome or Firefox according to the current project in global-setup.ts?

see the code about projects in my playwright.config.ts

  projects: [
    {
      name: 'chromium',
      use: {
        browserName: 'chromium'
      },
      timeout: 400 * 1000
    },
    {
      name: 'firefox',
      use: {
        browserName: 'firefox'
      },
      timeout: 400 * 1000
    }
  ]

in my global-setup.ts, I want to launch Firefox to login when I run the test using npx playwright test --project=firefox, and launch Chrome instead when the tests are run with npx playwright test --project=chromium.

I tried to set up an environment variable before starting test, something like set BROWSER=firefox, and check process.env.BROWSER to launch different browser in global-setup.ts, it works, but I guess Playwright could have built-in feature to support such case without defining extra environment variable.