Greetings fellow monk ,

I'm sorry but i ( strangely ) don't have sendmail installed on my machine , but i do have a package and i gave a look at it to give you this help before the heavy cavalry arrive and solves this

I thought that sendmail , being an old program , and widely used , there must be a good documentation . In my package , there is no less than 12 man pages ... Among these , i might advise you to look at the 'aliases' , 'praliases' and 'newaliases' ( doing a 'man aliases' , and so on , on the command line ) . But also , certainly , if you don't find your heart's desire , try 'man sendmail' , there'll be certainly there directives to tell you where to look at ...

Tomorrow , i'll install on my machine ( i really don't know how come i don't have it ... ) , and i'll pass by to tell you more if nobody else showed up here .

In the meantime , good search in the man pages ...