Can we reject mail yet still deliver it?

First off: DCC ROCKS!!!!

I got it up and working and its catching almost every bit of my spam.
Great solution. Thanks to all the developers.

I like the idea of saving spam for reasons of accountability,
prosecution and intrusion detection.

But I would rather my sendmail respond to spam requests with a
ERROR:"550 We don't accept mail from lower-than-dirt spammers"
so that they get the message.

Is it possible to have sendmail respond with a 550 rejection error
but still deliver the article to the recipient?

Also could somebody point to the spot in the source code that
a) makes the decision to reject or accept the message, and
b) where the X-DCC- header string is built?

I want to modify the X-DCC-header string to look like:
X-DCC-XXX-Metrics: XXX 1012; Body=1 Fuz1=1 Fuz2=many Action=reject

So that my mail filters can be specified to search for all DCC rejected
mail accurately.

Thanks,

- Jeff