in that case fubar@somewhere.com going to got 3 emails. The first one send directly from the requestor, a second on send by RT because fubar@somewhere.com are in the CC, and the third one because fubar are in the admin group of the queue.
I known everything are normal, but is they are a way to make something like
If not (email_address_from_cc \in Admin_CC_queue) then
add_to_cc(email_address_from_cc)
fi
instead to add every email_adress_from_cc unconditional to CC for the ticket ?
You can include arbitrary code in Perl templates (assuming you’re the RT admin and are thus allowed to generate Perl templates in addition to “simple” templates). If it was just this queue you needed to do this on you can have a queue specific template with the same name as a system one that implements this additional logic for you, generating the email if they don’t match up and a blank output (so no email) if they do.
I would approach this problem differently. I would disable the correspond scrips that send emails by default and create a scrip with the condition for web correspondence. This way if an email correspondence is recorded via email the recipients will not get a duplicate email. This helped me to setup soemthing similar to our system “OnWebCorrespond - Request Tracker Wiki”