Combine multiple coupons to one coupon code
The extension allows you to combine multiple Magento core coupons to one coupon code. Define the tiered coupon code and select its sub-coupons.
Later on, when the customer applies the tiered coupon in the cart, the extension will try to apply all its sub-coupons one by one, according to their sort order. The extension will stop, once it encounters a valid sub-coupon with "Discard subsequent Rules" flag set to "Yes."