Option to enable/disable "Discounts" on each price tier

We sell many of our products with a fixed price quantity discount. However some larger customers get the "best" price, regardless of quantity. This is set up as a separate price tier. However the quantity discounts are also applied which gives a further, unintended discount. Currently the only way around that is to create custom pricing for each product for each customer on this price tier. This causes a bit of a nightmare when there is a change in pricing. Ideally we would like to be able to turn off the Discounts for this price tier.