1. A computer program product, the computer program product comprising a computer readable storage medium having program code embodied therewith, the program code executable by at least one processor to: associate, by the at least one processor, a metadata field with one or more documents in a first document collection and in a second document collection to link the documents based on a relationship defined by the metadata field; in response to executing a first query, display, by the at least one processor, at least a first document in the first document collection and a pivot facet that is used to trigger a new search for documents related to the first document based on the metadata field; and in response to selection of the pivot facet and the second document collection, generate, by the at least one processor, a second query that includes a value of the metadata field; and execute, by the at least one processor, the second query against the second document collection to locate at least a second document that includes the value of the metadata field.