shopping cart price rules – How do I override tier pricing when using a discount code?

I need help overriding the tier pricing when a discount code is applied to certain SKUs. For example, when customers buy 5 of a certain item, it automatically adjusts the price of the item in the cart.

I have a promo code set up for 25% off select SKUs. The problem is that these SKUs also have tier pricing. The promo code works perfectly up until a customer adds 5 to their cart. It then applies the tier pricing and the discount.

Example 1: Customer purchases a single product for $349.00. They used a promo code to receive 25% off. They save $87.25, which then reflects the new total as $261.75.

Example 2: Customer purchases the same product ($349.00 each) but they purchase a quantity of 5, which falls into the tier pricing. When added to their cart, the price changes to $332.00 each. They then could apply the promo code to receive 25% off.

We don’t want them getting both the tier pricing AND the discount on the promo code. If they use the promo code, the tier pricing should be disabled. Therefore in example 2, it should be $349×5 = $1745 with 25% off, leaving their total at $1308.75.

Is there anyway around this?