Tax Rules to Supersede One Tax With Another

Hi,

I'm wondering if it is possible to create tax rules to have mutually exclusive taxes.

For example:

In a given US state, we would like to have this logic for our three taxation levels (State, County, City):

1. Always apply State tax.

2. Apply City tax if it exists.

3. Apply County tax UNLESS City tax exists.

Hence, the goal is to have the City tax supersede the County tax.

I'm not sure how this can be configured. I believe a (probably very maintenance heavy) way to do this would be to maintain a geography of cities that have a tax and have the County tax determined to be not applicable for these locations. Is there a way to do this?