Help needed to configure complex tax

Hi,

I am in the process of completing our store.

The problem I am faced with is the VAT calculations. We sell items that help the elderly and the disabled. All of the items we sell have VAT on them, but on some items if the purchaser is elderly or disabled they are entitled to VAT releif. To make matters worse the VAT releif does not apply to all items.

To sum up we need to configure the store so that

1. every item has a before tax and after tax price
2. when customers complete registration if they select an option that they are elderly or disabled they get charged the exc tax price on the items that qualify and the full price on those that dont.
3. when a customer that is not elderly of disabled registers they get charged the inc tax prices on all items.

Is the above possable, and what is the best way to approach it?

Hope this makes sense,

Thanks,

anthony