[Exim] Configuration Help

Hello everyone
I'm looking for help in configuring exim like:
mail server has two or more domains ex
domain1.com
domain2.com etc etc
and there is also few users, for example user1 nad user2
and one alias calles "alias" ;)
now, if email gos to alias@??? user1 and user2 gest e-mail
i dont want this to work like that, if messahe goes to alias@???
message should go to user1 mailbox
but is message goes to alias@??? mwssage should go to user2
mailbox.
is this possible ?

regards
WS