other shipmentcost for a category

For a musicstore I use woocommerce as a webshop. Everything works fine and my customer is very content using the webshop.

Only I have one question concerning shipmentscost.

Every order below 50 euro the shipmentcost is 9 euro. Above the amount of 50 euro the shipmentscost is for free. Therefore I use ‘Special Delivery’. Now my customer has a categorie in which the shipmentscost is 2.50 euro. If I use ‘fix-rate’ the choice of shipmentscost of 2.50 and the above cost of 9 euro both appears. So it is clear that I have to use ‘Special Delivery’ also for the last one I noticed.

But how can I do that….?

Thanks

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