[Exim] queue_only only from certain hosts

Hello,

I am wondering if it is possible to queue mail only from certain
hosts (and attempt immediate delivery of mail from everywhere
else). In other words, rather than run in "queue_only" mode, I would
like to run in "queue_only_if_from_this_host" mode.

Thanks,
Nick.
--
Nicholas Blackaby, ISD, UMIST.
n.blackaby@???, 0161 200 3208