[Mailman-Users] How to avoid dup copies to *multiple* email lists?

[Matt England]

How can someone subscribed to 2 (or more) emails lists from the same 
GNUMailman email server avoid duplicate copies of emails that are sent to 
both (or more) of these email lists?

My 2.1.6-rc2 server simply sends me multiple emails in such a case, even 
though I have the "avoid duplicates" set on my user-specific setting (which 
I believe is meant to avoid Cc:'s directly to me, and not necessarily the 
above scenario?).

-Matt