[Exim] remote SMTP defer to a different queue first

Hi All,

I am trying to pump large amounts of email to a few local (fast)
hosts. I have a 'queue' to process - this includes around 70% of
volume to my fast hosts, and 30% to the remaing hosts (the 30% are
bounces from the fast host....). The delivery goes fine, but the 30% of
bounces really slows things down (as it has to talk to hosts outside of
the network) :( Reading through the manual I could use the -R
domain.com - option, however 100% of emails are addressed to this
domain, so the -R selects everything (and doesn't help!).

Anyhow, to solve this problem, what I am trying to do is modify my
dnslookup entry to defer to a separate (non-standard) queue - This
way I could run a seperate queue runner on the other queue, and the
first queue would not be held up by external deliveries [it would just
pass anything external to a seperate queue and let the other runner deal
with it]....

I was after something like.... (lame psudo code)
dnslookup:
driver = dnslookup
domains = ! +local_domains
transport = my_spool
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more

then in transports -
my_spool:
spool = /var/spool/exim.out
defer

(I know the above won't work, but is there something like that I can do?)

I am unsure of how to get exim to save the email message to a queue (and
not to a mbox or maildir format).

Any suggestions appreciated.

Thanks,

Andrew