[exim] Allow mails only from senders in a partcular domain

hi all,

    I wanted to configure my mail servers to allow mails only from senders with mail id *@xyz.com and not any other domain instead of xyz.com. Please help me how to achive that.

I tried to do the following.

require verify        = sender
accept  domains       = +local_domains
accept !domains       = +local_domains
    !condition     = ${if eq{$sender_address_domain}{xyz.com} {no} {yes} }
drop    message       = Invalid Sender Address

Whether this will work. But how to populate the variable sender_address_domain.