I would like to journal a mail applying a Retention Category based on an AD Group. I know you can do it on Distribution List, per example if a recipient is member of a DL, then you can set a rule like this:
<RULE NAME='MyRuleName' ACTION="ARCHIVE_ITEM" RETENTION="7 Years Retention Category for HR"
<RECIPIENTS>
<DL>DL_Applicable_Employees</DL>
</RECIPIENTS>
</RULE>
So everytime a mail get in with one recipient of more member of this DL, then the mail get archive with the retention category set.
But can you specify an AD security group instead of a distribution group/distribution list (exchange 2003)? in Exch2k7/Exch2010, I think DL's are separate from AD.