Exclude lineitems from order level promotion

Hi,

I've been looking around the docs aka DotPeek to try to understand if it's possible to exclude certain lineitems from an order level promotion.

The use case is that the customer would like to give let's say 10% discount on the order if you buy for at least 500 SEK. However, certain items have discounted prices in the price lists so they'd like to exclude them from the order total used for treshold evaluation and reward.

Is this at all possible, or do we need to use item level promo instead? It would get a little tricky though since we'd need to find a way for the exclusions mechanism to treat the promo as order level even though it isn't.