Auditing a single user session

Hello all,

Please I have a challenge with auditing on oracle 10g database. Auditing is enable on a generic application user. However the volume of audit logs generated  is so enormous and it seriously impacts on performance especially during batch processing. I want to however disable auditing for that user but enable it only when the user is connecting from an SQL session outside the application.  Does anybody have an idea of how this will work.