[exim] String expansion in smtp_accept_max_per_connection?

Hi all,

I'm currently dealing with a situation where I need to limit the number
of messages a connection can send, based on the sender address. Some
external hosts should be allowed to send as many messages as they can
fit down the pipeline, whereas others need to be limited to a specific
number of messages per connection.

I saw the smtp_accept_max_per_connection variable is not subject to
string expansion -- are there plans to change this? If not, what have
others with this kind of requirement done to work around it?

Thanks,

-- DN
Daniel