I'm running a Liquid Web VPS and a couple of workers at one client I host would like to be able to monitor more than one email account they are responsible for simultaneously via webmail.
So for example, they would like to be able to view [email protected] and [email protected] from the one instance of the webmail app. They are currently using Horde for webmail, but would be happy to change, if that would help.
I know I can log into Horde as root and see all the email accounts, but can something similar be done for clients?
Another option is to use something like GMail's Mail Fetcher functionality to extract messages from these accounts and unify them in a GMail interface. Not sure if this is something that your client would like, but with Google Apps for your domain, it might be acceptable.
Finally, do these need to be actual mailbox accounts? You could just set them up as aliases that deliver messages to account@ and support@ into the user's personal mailbox.