All it takes is one message rule.
Go to Tools, Message Rules, Mail, New...
and the wizard will guide you through the creation of a new message
rule. You should wind up with a rule looking like this:
Where the message is from the 'Special' account
move it to the 'Special_inbox' folder
and stop processing more rules.
Note: Substitute your existing account name for what I've called
the 'Special' account. Any mail not meeting this criteria will go into
the normal Inbox.
The new folder can be named anything you want, and it can
be created as part of the rule creation process.
One thing to watch out for: When you compose a new email, the program
has no way of knowing which account you want, so it always uses the
default account. So, you need to check what's in the 'From' line and
select the other account, if necessary.
Thankfully, when you do a reply or forward, the program automatically uses
the identity associated with the account that downloaded that email.
The only way to make one account private is to set it up under a
different Windows user.
Gary VanderMolen