exim howto newbie ?

[christo <chris@platypus.net.au>]

hi to all that are able to shed some light with this problem i am having.

i have 3 domains on my system

dom-one.com
dom-two.com
dom-three.com

and 3 users on my system

userA
userB
userC

* at this point in time, exim is a fresh install on the system. i have been
through the eximconfig and entered relevent details for my
network and local domains hosted on this box etc etc.

from my interpretation of the docs, i assign email addresses to these users
by the following entries in the /etc/aliases file, specifically

userA@dom-one.com
userB@dom-two.com
userC@dom-three.com

so far so good....when i send mail to :-

userA@dom-one.com
userB@dom-two.com
userC@dom-three.com

all 3 receives them

now....if i send emails to userA@dom-two.com or userB@dom-one.com, userA and
userB receives this email where they SHOULDNT

my question is 

- why is that so ?
- how do i stop that ?

my current sitiuation is ...i have read the docs/manual.... but none of it,
from my interpretation of the content, tell me about my particular problem.
in fact...most of the documentation are very technically detailed....and in
most cases i am totally baffled....or lost ?!?

i appreciate the effort u put into sheding some light on this...

otherwise...if anyone could point out to where i can find some
"tutorials/howtos" i would appreciate it....

the docs, despite its thorough and comprehensiveness, is still overwhelming
and not IMHO a "howto/tutorial" so to speak. 

at this point in time , i have read all the manuals and looked at other
examples posted on the net. 

i am quite eager to learn this on my own...but need some help with learning
how to initially get pass exim's cryptic manuals and etc

thanks all for your help in advance...

regard
chris g.

p.s. i have tried using a particular example from one of the debian-user
post regarding "virtual domains" etc. to no avail....