Cost Calculator

Hello. I think this is going to be quite hard to explain but I am looking to find if my idea is evven possible.(and if so, I would then seek to outsource the project): I would like t o create a database/calculator in Microsoft Excel (or maybe Access for all I now) that works similarly to a digital form of a [login to view URL] a list of quite a few products and their prices to automatically add together (and if a discount is selected, have that amount deducted from the total). This is where it gets tricky though. The idea is that if you check a box to select a certain product, It will NOT ALLOW you to then mark a product that is not allowed to be included at the same time. (i.e. if you enter something, if will only allow you to go on to select other products that are compatible with the first) There are quite a few products that would be chosen from, and then also the different discount options that would deduct from the complete total. Is this possible? (Or more to the point, does all that actually make any sense?) Thankyou.