I have a bit mixed situation for my email accounts. 

Currently, there are :

info@mydomain.com

secratary@mydomain.com

employee1@mydomain.com

employee2@mydomain.com

me@mydomain.com

I want to change it to:

email sent to info@mydomain.com goes--> employee1@mydomain, employee2@mydomain, me@mydomain

email sent to accounting@mydomain.com goes --> employee2@mydomain.com, me@mydomain.com

When anyone received an email either by info@ or accounting@ or by his/her own email id, they should be able to respond from their own email address.

I already have quite a lot of items on all email id's and that's why I can't consider deleting any of them. 

So is there a way doing that?