Email routing config & rules

Hi ,

I ’ m currently trying to have a system for a team which allows them to forward emails to their already existing email boxes through another domain .

Imagine this is domain 1:
Imagine this is domain 2:

Everyone already has an email address on D1 (, for example, John Richard who joined the company in 2022’s email is jrichard2[email protected]

How would I setup email routing to allow users to just ‘input’ [email protected] (D2) or [email protected] (D2) and for that to forward to [email protected] (D1) ?

There are approx 2000 users .

( Sorry for link . com Discourse settings disallow me to post links )

Any help is appreciated ,
Thanks !