9My client has a requirement to have multiple discounts applied on his site. Some apply to all users, regardless of whether they're logged in or not, while others apply to specific MemberGroups only.

The problem is, that say I have multiple discounts for all users, there's no way to prevent the MemberGroup-specific ones from being added on top of this.

So, say I have the following:

• 10% off for ALL users (including unregistered)
• 15% off for ALL users purchases above £50 (including unregistered)
• 20% for ALL users purchases above £100 (including unregistered)

The discounts stack on top of each other, so I have to specify the actual discount percentage as 10/5/5 in each of the above. That's fine, however, if I then have the following:

• 20% off everything for Special Customers Member Group

I have no way to make the discount 20% on everything regardless of spend. I end up with discounts of:

• 20% (by specifying 10% additional discount)
• 25% (the original 10% + the Member Group 10% + the 5% for being over £50 spend)
• 30% (original 10% + Member Group 10% + 5% for being over £50 spend + 5% for being over £100 spend)

Does anyone know if there's a way to either prevent discounts from stacking or taking this scenario into account?

I've tried specifying negative discounts for the MemberGroup but these don't seem to get applied. Thanks in advance for any assistance anybody can offer.