Look under Order Total->Customer Group Discount
Supported OpenCart Versions:
What does it do:
This order total adds the ability to give customers automatic storewide discounts based on their customer group.
During checkout, if the total matches with configured rates, a discount is given.
Discount is based on the cart subtotal.
Optional settings for disabling discounts when other discounts are in effect (coupons, specials, referrals)
* Discount by % or flat fee
* Discount by ranges. Different discount rates at different price points.
* Discount ranges can be subtotal or qty based
* 100% self contained using the OpenCart Extension system
* Option to prevent discounting special priced products
* Option to prevent discounting if coupon is active
* Option to prevent discounting if an affiliate referral is in use
* Option to exclude discounting for products in certain categories
* Discounts automatically added to the totals during the checkout process
* Dynamically expands for all customer groups created
* Automatically discounts product tax (if applicable)
* Different discounts for each Customer Group including Guest Checkout
* Individual Minimum Totals for each group before the discount is active