Group filter not limiting values as configured

[beachcamp]

I have a filter widget setup with 3 filters, all on the same data.

I want the values available in the drop downs for each filter to respect selections from the other filters.

My expectation is that this option:

Will accomplish this. However it seems to have no effect at all.

Is this expected behavior, what am I missing?

Here's a bit more of my configuration:

Thanks!