I have two eDir trees i am synching....a flat tree and a departmental
tree. I am trying to create a policy/rule that if someone creates a user
in the departmental tree (unique in its own container, but not unique to
the entire group of users) with a CN that already exists in the flat
tree..... an email will be sent to the admin account to notify him that
the user was not created. I have tried to figure out how to write
this..... but I can't get it. This is what I am trying to do:

If I'm creating a NEW user
and if the CN of this user already exists in other tree
Send email

Should it go in the Matching Rules??? Any suggestions would be appreciated.

Thanks, Jordan