Samples via Invoice not to hit COGS

As part of our normal business processes, we often send out samples to our customers. When this happens we take the normal approach of creating an invoice in our system and setting the amount to $0, as described here:

https://netsuite.custhelp.com/app/answers/detail/a_id/26179/kw/sample%20invoice

However, since we aren't actually selling this product, we don't want the deducted inventory to hit COGS, but a separate expense account meant for samples alone. This is a bit unfortunate for us since the system looks to the item's COGS account to figure out where it should post.

I don't think this will be too hard to get around, but before I start creating new items, scripts and workflows just to handle these samples has anyone else been through something like this before? I just want to check my bases before I start throwing things together to see what works.