Prevent coupons from being used by member groups

I have almost completed setup for my storefront that contains special member groups for discount pricing and also want to set up coupon discounts for those that are new members as well as promotional discounts.

My problem is I see no way to restrict members that already have special pricing from using coupon codes I make available as a promotion. This would allow wholesale and other discounted members to apply an additional % off which is not desirable.

Is there anyway to limit coupons to none special group members?

I saw a couple posts searching where others were having this same trouble and hope there is a way to fix this double discount problem. I downloaded a plugin that sounded like it would fix this issue, but was not written for 1.50 (Online Group Pricing)

Thanks

I found the code I needed to rmove tha ability to apply coupons to groups http://www.zen-cart.com/showthread.php?191953-Blocking-usage-of-Group-Discount-amp-Discount-Coupons&p=1100913#post1100913