the shipping state is stored in the eCartCheckoutForm_shipping_state_province session variable.
you can set up different tax rules for each shipping state. in the trigger section use the Session Variable exists and Based on session variable value to set up the conditions to trigger that tax rate.
so you would set one rule for one shipping state
another for a different shipping state and so on.
the triggers will apply the rule only if the conditions are met causing an If else scenario.