Saving From A Specific Computer

I have a My Book Elite 2TB.  I am story rather lengthy documents so want to use the ED to store just those documents.  Is there a way to store the documents I want to download on to the Elite in a particular folder so that it only downloads those, rather than grabbing every piece of material that is placed on my computer.  This is a second computer and I do not want to save everything I put on it.  Thanks.