[Exim] veryify senders but allow userid-*****

I haev the following in my exim.conf file. This stops me from sending
email as [validid]-[something]@domain.com Is there some way to allow
this without opening up email to anyid@....

The rational is that, email sent to listservs goes out under the email
addy of [validid]-[listname]@mydoman.com

sender_verify = TRUE
sender_verify_fixup = FALSE
headers_sender_verify = TRUE


Thanks.