[exim] How to Domain aliasing

Hi,

I want to create domain aliaing in exim.

e.g
test1.com is alias of test2.com. So when some one send mail to
particular user of test1.com then that mail will be forwarded to
test.com of that user.

It is possible in EXIM ? I know the user aliaing but want to create
domain alias.

OR have to change in vpop3d ?
We are using vpop3d for pop.

Please rely me asap. Its very urgent for me

Thanx
--
M.A.Shaikh
Linux System Administrator