email address rewrite and send back out

[bmars69]

Hello,
I need some help !! My company is changing email addresses as well as not hosting onsite any longer and going to a hosted solution. What I need to do is:

any mail received to someone@subdomain1.domain.com needs to be changed to someone@subdomain2.domain.com and sent back out to the new mail server. This is just a gateway so to speak that is needed only to change the subdoamin part of the email address and send it on. It will not store any emails.
Does anyone have any ideas on how I can do this ?

Any help would be appriciated.

thanks,
Bruce