Blackout Zones

I'm wondering if there's a way to create a "blackout zone" globally so that anytime my moving heads pass through that zone they shut their intensity off (or lower to some predetermined level). Basically, I've had congregation members struggle with the beams hitting their faces and causing headaches. This got me to start thinking about seizure possibilities and other medical conditions, and so I'm wanting to create a 'safe area' in the room where we can guarantee those members that the lighting effects will be minimal or non-existent.

Thanks in advance for any help!