Hi Alan and Welcome to the Forums!!
This is done with our price levels feature:
Under Admin Panel > Inventory > Price Level manager, you will need to add the desired price level(s).
Then under Admin Panel > Inventory > Product Manager > Search for product you wish to apply the price level and click edit. Then click the advanced options link in the upper left hand corner above the normal tabs. Add the desired product price for each level or select the call feature to restrict that level from being able to order the product and click save. If you wish to restrict non-logged in customers from being able to purchase the product, you will need to check the call option under the general tab of the product editor. Repeat this step for all desired products.
Under Admin Panel > Customers > Customer Manager, search for the desired customer profile or create new customer profile for customers that need to be placed on a particular price level and click edit. Edit the customer profile and select the desired price level, then click save. Customers will need to know their email address or username and password to login to be able to order at the desired price level. Make sure that login link is available on your site: index.asp?pageaction=login.
Hope this helps!!
Thanks
Brian