How to change to name of "sender"

[Guest]

Using exchange5.5 + outlook2000

When userA send email to the other , we want the "sender" from the receiver
show such as our company name, but dont show "userA", Any way can do so ?

(And this purpose just for short term only)

thanks a lot

 

[Guest]

1 more condition
when receiver reply that email, it should reply to userA

I know I can modify the display name from the exchange, but any other way
too ?