Both the individuals and orgs are all already set-up as contacts in CiviCRM. I have the details of the contacts in a csv file (row headings along the lines of: Title, 1st Name, Surname and Organisation name). I had assumed by importing the individuals and setting the relationship to match the organisation name, CiviCRM could set up my new relationships. But no matter which import options I specify they are not created.

Can anyone suggest how to do this; for example am I filling or updating duplicates, and how should I match the data fields?
Thanks a lot