Federated search categorization

I'd like to associate the external content with existing zd categories so that when you do a search 'By Category' the external content will show up in under that category's search results.

I can try to fudge it by using the associated external record's 'Type' or 'Source'. i.e. create a 'Type' record with the same name as the category i.e. a 'Widget A' category would have a 'Widget A' 'type' record. Not a great solution though.