How do I get firebase hosting predeploy to run per target?

There is a firebase.json like this

"hosting": [
    {
      "target": "site-b",
      "predeploy":cp ".env.site-b .env",
    },
  {
      "target": "site-c",
      "predeploy":cp ".env.site-c .env",
    },
  {
      "target": "site-a",
      "predeploy":cp ".env.site-a .env",
    },
  ]

Deploying with a single target will work, but if multiple targets are specified, the .env will all be the same because deploy will start after all predeploys have been executed, which will not work.

I want to use Github Action FirebaseExtended/action-hosting-deploy@v0 to check the preview of multiple sites, is there a workaround?