event-driven connection tracking

[Mr Dash Four <mr.dash.four@googlemail.com>]

Is it possible to use event-driven connection tracking - with 
conntrack-utils or by other means?

Ideally, what I would like to do is 'register' a handler for particular 
connection events (when new connection is established and then closed 
for example) based on particular pre-defined filter (say, by protocol, 
source/destination ip etc) and execute a program code/function (if done 
programmatically) or a script (if done outside the connection-tracking 
domain) to do what I want?

Currently, the only way to track such 'events' is if I include a 
separate chain in iptables tracking a particular connection (and logging 
the event via a normal log jump), but that is not enough for me as I 
also need to trigger a full dump based on that particular 'filter' and 
end this dump when the connection is closed. Any ideas?