Change to PHP Shopping Cart

I require a new feature that will link together one or more products and combine them together before adding them all to the shopping cart. For example: Product 1 is a Diamond Ring Setting. The user clicks on this product to choose it. Before he can add it to the shopping cart he must choose Product 2, which is a diamond. When he goes to Product 2 he should be able to select any options that are available. Once this is chosen he should then have the option to choose Product 3 which is side-stones for the ring. Again he should be able to choose within 3 any options that are available for it. Once he has selected these products, he should click an "Add to Basket" button which adds all 2 or 2 of these products into the Basket at the same time. The total price should be the value of each of these products added together. You can see the way the system is currently set up by looking at <[login to view URL]> This is currently using a form to pass data through to a 2nd product on the 2nd tab of this page. I am unhappy with how this is currently working, but it is critical that all the current features will continue to work, such as the way the the price of the diamond on Tab 2 is updated as you choose different options. I should add that the shopping cart currently has a "Group Product" function which means that you can define Product A to contain Products B, C & D. Ideally , all that needs to be done is to make some changes to the Group Product function that will allow you to include a product which has options and a varying price which is added to the main product to calculate a total price. ## Deliverables 1. This project must not disable any functionality of the current software. 2. I would like the product data to be managed through the existing backend administration. For example, for the product shown above, this would have fields that I can set through the product admin that tell the software which other products to link to. Eg field_01R="D001" tells the software to link the product code D001. The field name ends in "R" to indicate that this is required, ie the user must select this product before he can add this product to the cart. field_02="D192" - this tells the software to link to a 2nd product, however this 2nd product is optional ie the user can choose not to include it. 2. Similarly, if the user wishes to delete these products from the shopping basket, he should only be able to choose delete Product 1, but deleting this product will automatically delete Products 2 & 3, since they are grouped together. 3. I require that the PHP is created in a modular way in a similar fashion to how the cart currently works. This means that html templates can insert code using syntax such as {[login to view URL]} to display data. 4. It is critical that when linking products the link should be done using a href link and not using forms and post/get data. 5. Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 6. Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 7. All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Apache, MySQL, PHP, Internet Explorer 6.0+