It should be possible to set the email_on_error|warning|success temporarily with JobScheduler API

When you have a job configuration like this

<job name="job3">
<settings >
<mail_on_error ><![CDATA[yes]]></mail_on_error>
</settings>
<script language="shell"/>
</job>

you probably want to set the propertie "mail_on_error" in a post processing script spooler_task_after to avoid sending an email on certain condition. E.g. if a exit code <> 0 is ok, should be stored in database, should let the order proceed in job chain but should not send an email.