I've got a search results webpart set-up which returns items from a large document library. Alongside it is a refiner web part which refines the results based on a managed metadata field set on those items (each document is tagged with multiple metadata values). Selecting multiple refiners would result in an OR-type query, returning all results tagged with either of the values. But I would like to have results based on a AND-type query. Is this possible? and if yes, how?