[exim] Referring to files relative to main config file

Hi.

I was wondering whether it is possible to refer to files used in the exim
config (for example in lookups) relative to the directory the main config
file was loaded from.

For example, imagine I had a file called 'local-domains' lying next to my
exim.conf in /etc/exim. Usually, I'd have to refer to it as
'lsearch;/etc/exim/local-domains'. This hardcodes the path the file is in.
What I'd like to do is to be able to say 'do an lsearch on a file called
local-domains that is in the same directory as the exim.conf
you loaded'.

Is this possible?

Thanks.