[exim] ACL and id message check

Hello.

Is it possible, in an ACL, to check if a string is in the ID of a message?
For example, if the string '.squirrel@' is in the message ID:
id=10635.192.168.0.30.1097764020.squirrel@192.168.45.79

Thanks for your help,

--
E.Bullier