[exim] How to delay multiple adresses in TO CC or CCI ?

Hello,
have users that put hundreds of addresses in their TO, CC or CCI fields.
I know this is bad practice and they should use maillists, but most of
them don't know how to do this.
So to avoid overloading distant recipient servers, is there a config
possible so say a mail with 100 recipients, will be sent one by one
with a delay of 1 second ?

Best regards,
Yves