Hi David,
Well, there are two different ways of prioritizing results:
– Either prioritizing them one-by-one, globally. In this case the priorities apply to any search phrase.
– ..or prioritizing items within a category or matching a custom field (group priorities), in this case a search phrase rule can be implemented as well.
In short, that is not really possible, however you can either prioritize those items globally, on prioritize certain categories or items that contain a specific custom field.
I hope this helps anyway!