Reserve/protect area from copperfill / massfill

Hallo at all,
I have a high voltage area on my layout and wont have a mass near by. Can I protect this area againist the massfill? This is what I want:

I got this by circeling the area with a dummy wire and removed this in the .svg than. But in all the copies and mirrors it is a little painfull. (btw: for what is this all needed?) And what should I do if I have to export PDF or something like Gerber?

I wondering if there is no solution - everybody who use a relais for switching 220V~ have the same problem.

I hope somebody can give me a hint.
Thanks in advantage

There is a thing at the bottom of the core parts that says copper fill blocker.

Very good, exact what I am looking for. How do I close the thread?