If you are refering that you have two explicit keys and you want a collection of the docs for those keys then notesdocumentcollection can help you.
Either create a loop or code which will first get all the document by key using the first number key and put that into a document collection.Again use getdocument by key for the second key and put the docs into the same collection which contains the docs collection of the first key.Now you have the all the docs matching both the key in a single notesdocumentcollection.Now its up to to play with the collection.