rthompson wrote:

Correct me if I'm wrong

I could under one single Email address open different pst files

This is correct and the mail address has nothing to do with it.

And in each I would have just a few specific sub directories

Or not. You don't need folders if it's a separate PST, but nothing stops
you from having them so that you can further organize your data within the
PST.

So from a main outlook session I could save the incoming mails to
various other pst files???

If that's what you want to do. You were talking about older messages,
however, not newly-received ones. You can have incoming messages moved by
rule to other folders, either in the default PST or in any others opened in
the mail profile, if you wish or you can move them later manually or by a
manually-run rule if you intend periodically to move things subject to the
same conditions.
--
Brian Tillman