Pick up (at store) shipment option - disable for some prods?

Hi

How can i disable the pick up option (in shipment tab under modules), for some products or categories of products.

Say i have products that always go from manufacturer to customer. Then i need to disable the option for local pickup at store or similar, for this category or product.

This means that customer has to pay shipment for the product, as i always send it directly.

Can this be don in Opencart 1.5.x or do i need a extension to do this?

kind regards / Slim