Wholsale Prices and Discount / Coupon Code Bug?

Here’s the setup:

We have 2 types of customers to our site:

  1. Retail Customers
  2. Wholesale Customers

    If we have a discount coupon code for a specific Product - then this code can be used by both the retail customers and wholesale customers…

    e.g. say we have a code (for $15) for a product, MSRP; $100 (wholesale price: $60)

    the way it is setup… even if the wholesaler uses this code… he/she can also get this discount (making the price: $45) ← which is not acceptable.

    What is a workaround? Any Tip or Trick will be appreciated.

Can’t you turn off / assign codes for certain membership levels?