Sendmail Aliases

I’m running Sendmail on a Red Hat server. I need to be able to route incoming internet email to a local linux mailbox AND forward it to an external email address. If I did (in /etc/aliases):

jdoe: jdoe@somewhere.net, jdoe

but…this would result in a mail loop. Is there a way to tell aliases to point to the local mail file?

I’d like to do it with /etc/aliases. But, if anyone knows of a better way (maybe using .forward?) I’ll take that advice too.

Thanks in advance.

Christian