wrote:

I have 1 email account, with is shared between me and my girlfreind,
we each have our own email address, but all our mails go in to one
joint inbox, using something called Email Alias, that our ISP use.

The problem is that we get each others mails, and we would like to
setup a rule so that the mails not intented for the person that
recives them is automaticly deleted in his/her outlook and is left on
the server so the other can get it when checking their mail.
....snip...
Basicly i would think it was just to set it up so that the messages
arent deleted on the server for a few days, and then sorting it so
that email with the wrong recipient automaticly gets deleted.
But i cant seem to get this to work.

This is exactly how to do it. You create a rule that deletes all messages
and add the exception "except with specific words in the recipient's
address", specifying your own alias as the "specific words".
--
Brian Tillman