Hi Emmanuel,
thanks for the links, now I understand. You are right, for local HMI you can simply kill Chromium and reload it with a different starting page. For me, this is not appealing at all, but that's not important.
You can always run a bash script from REXYGEN using the EPC function block, killing and restarting Chromium in case of an event. See example 0202-11 for inspiration.
Best regards
Jaroslav