I tried this once and everything hung up
Group Pricing or Discounts 101 
1) Goto Orders & Shoppers
2) Create "Discount" Shopper Group - I named one of mine Discount40 for 40% off MSRP and labeled same in description.
2a) "
Enable shoppergroup specific price display" - Check the box

2b) "
Show Prices" - Check the box

2c) Configure labels and prices for what you want displayed with this group - I checked both boxes for "
Final salesprice" only, the others left blank

2d)
Save & Close3) Goto
Products - Click on
Taxes & Calculation Rules (see where this going yet

)
3a) Click on NEW (Big Yellow Plus icon, upper right corner of window)
3b) After new blank window opens, name your new "
rule" what ever discount you have in mind, I named mine "40% Discount off MSRP"
3c)
Description - I filled in "40% off MSRP"
3d)
Type of Arithmetic Operation Select -
Price modifier for Profit Margin3e)
Math Operation Select
-%3f)
Value - Type in the value of the percentage discount you wish assign for this rule - I used 40

3g) Set the
Currency3h)
Product Category Here you can assign this rule to specific Product Category(s)

Leave blank otherwise

3i) "
Shopper Groups" Now here is the BIGGIE - This is where you assign this rule to the Discount Group(s) you setup previously

3j)
Country - Here you can apply a rule by Country(s) Leave blank otherwise

3k)
State / Province / Region - Here you can apply a rule by State, Province, Region

Leave blank otherwise

3l)
Visible for Shopper - Check the box

3m)
Visible for vendor - You decide here for yourself

3n) Set
Start Date and
End Date as you wish

3o) Check over your settings and once satisfied, "
Save & Close"
Now you should be able to assign a specific user to a Discount Shopper group and when that "shopper" logs in, the prices in the catalog should automatically change to reflect the discount you set for that group

Try it and see for yourself

Once you realize how the groups and rules work together you can readily see how many possible combination's there are for setting
pricing and
taxing structures

I hope this helps
