Magento Catalog Structure Amendment - URL rewrite

Our site and typical magento catalog structure is root, catagory, sub catagory etc with products able to be located in one or more of the catagories. EG. [login to view URL] will display a list of all products listed in catagory "birthday-flowers". Therefore, the address for a typical product "product1" in the birthday-flowers catagory will be found in [login to view URL] . If the same product was included in catagory "flowers" it will also be found at address [login to view URL] The use of canoninical links is designed to overcome seo impact of duplicate content however i prefer for the product itself to be loctated in a single location irrespective of the catagory it is listed in. I only want the product1 itself to be found in [login to view URL] even if it is listed in many other catagories. Therefore a subcatagory list showing a product will always show it to be in the lower level catagory only. please refer to the operation of 1300 flowers com au for a good example of this... (not magento site)