[exim] callout caching

Howdy all,

In the docs
http://www.exim.org/exim-html-current/doc/html/spec_html/index.html#toc0351
it states

The expiry times for negative and positive address cache records are
independent, and can be set by the global options
callout_negative_expire (default 2h) and callout_positive_expire
(default 24h), respectively.


Is there any to specify different expiry times depending on if its a
recipient or a sender being verfied?

TIA
Andrew