[exim] Logging stats via script?

Hi guys,

I'm looking for a little bit of guidance here from all the experts.
Basically what I'm trying to do is get Exim to run a script for every
successfully sent/received mail it deals with. Ideally I'd like to pass
the sender/recipient and size of the message to a script which will then
record it to a central database.

Can anyone point me in the right direction here or tell me where the
correct place for this would be? I'm using Exim 4.69.

Thanks in advance,
Marc