on the link bellow

http://www.rubberduckbathrooms.co.uk...&cPath=3_13_56

you will find 7 products.

the products are a bathrooms suit which can be purchased, how ever all items can be purchased alone or as a suit. if the items are purchased as a suit it costs £299

what i want to know is how can i make it so if a customer buys a bath, toilet, bidet and basin it costs £299 instead of the total price of all added together.