Excluding events by command

Hi all, I'm trying to exclude cron events from audit logging. I can't see how can I do to only exclude this kind of entries: ---- time->Mon Sep 17 11:00:01 2012 type=PATH msg=audit(1347872401.521:5212): item=0 name="/etc/pam.d/system-auth" inode=33635 dev=fd:00 mode=0100644 ouid=0 ogid=0 rdev=00:00 type=CWD msg=audit(1347872401.521:5212): cwd="/var/spool" type=SYSCALL msg=audit(1347872401.521:5212): arch=c000003e syscall=2 success=yes exit=5 a0=2b5b7b627300 a1=0 a2=1b6 a3=0 items=1 ppid=11640 pid=1965 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="crond" exe="/usr/sbin/crond" key=(null) ---- I didn't see any option to exclude events by 'exe' or 'comm' field. Any hints? Thanks in advance, Laura