Problem with multiple sites and crossposting

Hi!

I have two sites, both running sn 0.3.3.  There are a few newsgroups,
some of them being hosted on computer A and some of them on computer
B.  Computer A connects to B at regular intervals and reads the groups
hosted on B, and vice versa.

Now, recently it happened that someone cross-posted to three groups:
two of the groups were hosted on A and one of them on B.  What happens
is that SN gets somehow out of sync and the message for the newsgroup
on B now reappears every few hours as a new post.  Over the weekend,
we managed to accumulate the same post tens of times =)

For a while, I got things going by resetting the SN database and
expiring all the relevant articles, but then somebody crossposted a
reply (apparently from a local message cache) and the whole shebang
started again.

Does anyone have any idea how this could be prevented?  Is this a bug
in SN or in my setup?

(Yes, we want some of the newsgroups hosted on A and some of them on B
- because we wish to save bandwidth and synchronize at discrete
intervals).

-- 
Janne Jalkanen                          Regex Pty Ltd
[email protected]             Level 11
Tel: +61-438 428 041                    530 Lt Collins St
Fax: +61-3-9909 7510                    Melbourne, VIC 3000