[exim] outbound discard all filter for cpanel twisted exim

Hello,
I have a large number of servers on which we do not want outbound email,
however it's pretty much impossible to kill off Exim on cPanel servers
without creating far worse issues.

What I would like would be to create a discard filter that takes any
outbound email that hits exim and sends it to the great circular file in
the sky.

I'm familiar with creating filters for inbound email in exim but can't
really find much on doing the same for outbound. Do the inbound filters
also apply vs outbound?

Thanks,
PM