In another forum, this is whoinix forum and you told me to look for the answer somewhere else.
There are some methods to do that (whonix gateway with w "kill switch like") but i dont master them.
I did read some methods of messing with windows firewall to block any non vpn connections, including virtualbox, and that sounded complicated, including messing around with many programs.
Then i found 3 people that do that in a MEGA SIMPLE way, messing with adaptors in virtualbox.
Somehow, linking the NAT first virtualbox adapter to the VPN WINDOWS ADAPTER.
Anyway, i am not an expert but i remember you, patrick, some years ago, writing about "DONT USE BRIDGE, USE NAT" in whonix because was safer.
So, in the HOST>VPN>WHONIX scheme, whould be GREAT to teach us how to do that in a SAFE way.
Plus, you can add that to whonix docs, and more:
Since i did read in whonix documentation a warning about HOW TO CLEAN TOR ENTRY GUARD WHEN CHANGING LOCATION, to change vpn to HOME location, in case of a disconnect, we would also endanger disclosure.
So, please, is faster you teach us how to do that than write all that you did to tell me to find help somewhere else.