Create Group from a CWYW document

How does one create a group from a document is process. I am writing my dissertation, and I need to be able to analyze my references using various criteria. I have tried manually keeping track, but it has become too much to track. It would seem that I could create a group from the citations contained within the document. All of the information exists to create a new library but this has limited usefulness. Does anyone have any suggestions as to how I might aggregate all of the references used in a single document into a group? Thanks!