Afaik this can be achieved if you have 2 mini’s (or similar) in the same room. I’m not aware of any other way yet.
I let this speak up on one mini: “Okay google, okay, turn something on”.
The second “okay” is needed to give the bleep some time before the real command is spoken.
The second mini responds to the command.
Yes this is odd, I know
Make a virtual switch in Homey which appears in Google Home.
Make 4 scripts in Google home:
2 for turn on and off the Google device if the virtual switch turns on or off
2 for turning on and off the virtual switch in Google if the Google devices is turned manually. You want Homey to know what state the google device is.