AbleCommerce Shopping Cart Software

We are trying to do some tricks with special pricing and im not sure what all I need to do to make this work. I will try to explain:

We have users who can fit into 1 of 4 tiers of special pricing. We created these "tiers" as user groups, and then assign users to their group.
We then set up a pricing rule on a product that only applies to a particular tier, or several rules for multiple tiers. This allows users in a tier to have a set price for their product based on their group.

The trouble is that volume discounts still apply to the product, even if they get special pricing. This could potentially allow users to get prices that are below our cost, which is bad.

I figure that you could put in an IF statement that checks if the user is in a group to stop this. I dont know how many places I would need to put such code.

The product page would be the first one, but I dont know if discounts get applied elsewhere. How would I ensure that the special pricing applies and volume discounts get disabled through the whole order process all the way to the packing slip?

What about instead of having a global volume discount you can have a specific volume discount that should not be available to those user groups eligible for special pricing.

Not sure if that would work because we already have 500 volume discounts in play, each one named for a product or product line that it applies to. Each product essentially has its own volume discount, though not all products have discounts. I dont believe we have any global discounts. I think because of the number of discount variations we have, they just wanted to control each one manually.

Hmm in this case if volume discounts are already specific for certain products then you can extend the criteria and exclude those user groups who will get special pricing for that product. For example you have a product named My Product and there is volume discount My Volume Discount available on that product. My Product offers special pricing for some group called My User Group. In this case you can extend My Volume Discount criteria and make it available to certain user groups as well and exclude My User Group from that list.

Yeah I have started thinking that is the direction we will need to go in. I was hoping to find a way to do it without the need to modify all of the discounts we have made already. In any case, we are going to try to slim down our list of discounts, which should make it easier to do that.
What would be ideal is a checkbox on the edituser.aspx page which disables volume discounts for that particular user.
Is there any (simple) way to do something like that?

Even we want to turnoff volume discount for some user groups. Is there an easy way to turn off volume discounts. I am not sure how many places we need to modify or even if AC allows to do that.

Any help will be very much appreciated.

Thank you,
Carol