Coupon restriction options based on cart totals or qty

It would be GREAT to e able to restrict coupon use based on cart parameters. For example, allow coupon only is X+ qty of a product is in cart or if total in cart is over $X. 

My particular use case:

I sell courses and want to provide a group discount when 2 or ore people register together. I need the cart to recognize that 2 of the course tickets have been purchased and then allow the coupon to be applied...OR have it native in the product setup. Say, when setting up a product, you can have the option to offer a discount when X+ quantity are in the cart.