CRE Loaded, Cross Sell with Discounts on Combination Deals

Cross sell function needed with the ability to offer cross sell products at a discounted rate: We sell bedframes and would like to cross sell mattresses with our bedframes. If a customer wants to add a mattress into there shopping basket then that item gets discounted down. A perfect working exmaple of what we require can be found here: [login to view URL] ========================================================================== We have a heavily customised site; any programming must fit in with this customisation. Discount structures /rates must be user modifiable, i.e. stored in the database, NO hard Coding of variables. Discounts granted should be stored in the appropriate field in the Orders total table.