I have a bit of a dilemma since Royal Mail have raised changed their prices to extortion levels.

We had to increase our table rates across the whole site so that now the minimum UK shipping is £6.00, then we have £1.00 increases based on order value.

My dilema is with the ribbons that we sell as these are quite small and they do fit in the new cube sized boxes that Royal Mail will still post for under £4.00. Ideally, we would like to have our site set up so that customers checking out with only products from category ID 409 will be using a different table rate from anyone with products from a different category.

Is this even possible? If I were to duplicate the "Table" shipping module and call is say, Table409. How would I code the cart/checkout to differentiate between carts with only products from category 409 and all other carts?