[imp] Automatically change identity based on IMAP folder?

[Lloyd Zusman]

I manage my own DNS and email server, and I have several
different email addresses under a few different domain names that
are all managed under this same server.

I perform server-side message filtering such that messages to
different email addresses of mine all get stored under separate
folders within a single IMAP account.

I'd like to configure IMP so that when I open a specific folder
under this account, the return address, signature, and possibly
other items get _automatically_ set to folder-specific values. Is
it possible to do this under IMP?

In case this isn't clear, here's an example of what I'm doing:

Suppose I have the following email accounts that are all managed
on my server:

user1 at domain1.com
user2 at domain1.com
user3 at domain2.com
user4 at domain3.com

Note that these accounts span four different domains.

My server-side email filtering puts all incoming email to all
four of these accounts into separate IMAP folders under a
catch-all email address, namely email at mydomain.com. In this
example, suppose that the IMAP folders are named as follows:

INBOX.user1  (all mail going to user1 at domain1.com)
INBOX.user2  (all mail going to user2 at domain1.com)
INBOX.user3  (all mail going to user3 at domain2.com)
INBOX.user4  (all mail going to user4 at domain3.com)

Furthermore, suppose that I have separate "sent" folders for
each of these addresses:

INBOX.sent.user1
INBOX.sent.user2
INBOX.sent.user3
INBOX.sent.user4

What I would like to do in IMP is for the following parameters to
be automatically set whenever I am looking a a message in each of
these folders and then want to compose a new message, or when I
reply to any of these messages:

When viewing INBOX.user1 or INBOX.sent.user1:
... Return address automatically set to user1 at domain1.com
... Sent folder automatically set to INBOX.sent.user1
... Signature automatically set to a user1-specific value

When viewing INBOX.user2 or INBOX.sent.user2:
... Return address automatically set to user2 at domain1.com
... Sent folder automatically set to INBOX.sent.user2
... Signature automatically set to a user2-specific value

When viewing INBOX.user3 or INBOX.sent.user3:
... Return address automatically set to user3 at domain2.com
... Sent folder automatically set to INBOX.sent.user3
... Signature automatically set to a user3-specific value

When viewing INBOX.user4 or INBOX.sent.user4:
... Return address automatically set to user4 at domain3.com
... Sent folder automatically set to INBOX.sent.user4
... Signature automatically set to a user4-specific value

I know that I can do this by creating separate identities and
then manually switching between them. However, is there a way to
tell IMP to _automatically_ switch the identity whenever I view a
particular folder?

Thanks in advance for your suggestions.

-- 
 Lloyd Zusman
 ljz at asfast.com
 God bless you.