how to give discounts based on groups

[peaceandlove]

What i want, based on retail price, let say i will put $100 price for product A

A) If customer is retailer he will get 10% discount
b) if customer is wholesalers he will get 20% discount

I only want to set retail price , so is that possible based on group of user registeration they will auto the the discount? if so how

[Jörgen]

Create hidden category:
  10 % Retail Discount.
  Add product to hidden category
Create Dscount rule
  10 % Retail Discount
Create Shopper group
  10 % Retail Discount (Or use an already created group)
  Add shopper group to discount rule
  Add shopper to shopper group

Done

Jörgen