Humm, ok let me trying to explain this differently.
Instead of setting up the entire state of CA as a zone you would set up each county as a zone instead.
So for instance you would have CA - LA County, CA - Orange County, CA - Sacramento County etc.
So when someone from CA orders they have to select the county they are in, since it doesn't give them just CA as an option.
You then set up a zone tax for each county.
Is that any clearer?

LadyHLG