Data Importing and Updation with EA_Import for many2many field

Hi, I am using ea_import tool to import and update the data in forms. I am able to do import (if new) and update (if exist) successfully for all fields including one2many and many2one **but not for many2many**. Is there a way to do that with ea_import or with any other module or with default import functionality. I would like the following to happen for the list of records. Create if it doesn't exist or update if exist. I can give the data in any format required not an issue. Any idea of how to do this (**for field many2many**)?. Thanks for your time.