Multiple coupon codes on one sale


I wanted to allow my customers to use more than one coupon in a transaction. Case in point, I set up a coupon for the first 250 subscribers to my email list to get a free item (retails for $1). I also set a promotion up for email subscribers to receive $10.00 the purchase of items in certain departments. When I test and apply both coupons, the $10.00 off is reduced by $1.00. Also, the coupon only applies once, so if the customer purchases more than one item in the affected departments they only get one discount.

Is there a way to allow multiple coupon codes on one transaction? Is there a way to allow the discount to apply to multiple items?