User Specific Auditing

We have enabled informix auditing using onaudit utility. Currently we enabled it only for DDL changes, for achieving this we used _require mask. Now we want to audit DML for all users except application user (say app_user). When we use user specific auditing (in term of auditing filter execution) it comes at the first step then _default then _require and finally _exclude. How can we use any mask (UPRW) for all user except application user. We are using following environment $ onstat -IBM Informix Dynamic Server Version 11.50.FC8W3 $ uname -aSunOS test 5.10 Generic_148888-05 sun4v sparc SUNW,T5140