Make checkbox question mandatory

Hi,

I was wondering if there is a clever way to mark a question containing checkbox questions (more than 1 answer possible) mandatory that at least 1 checkbox is ticked.

In the example: I can define an error message for Container 6 if no checkbox out of those three are ticked. I know I can make each single checkbox mandatory, but that's not the point and would be detrimental in my survey case.

Thanks!