1. A method, in an information handling system comprising a processor and a memory, of identifying cluster relationships for searching across a plurality of corpora, the method comprising: identifying, by the system, a plurality of different cluster classifications for a corresponding plurality of corpora; classifying, by the system, entity information from documents stored in the plurality of corpora into the plurality of different cluster classifications; applying semantic analysis, by the system, to identify entity relationships between entity information classified in the plurality of different cluster classifications; determining, by the system, one or more scores for each identified entity relationship; identifying, by the system, a cluster relationship between at least two cluster classifications based on the one or more scores for each identified entity relationship; and searching, by the information handling system, at least first and second corpora corresponding to the at least two cluster classifications having the identified cluster relationship.