keeping emails as unread using multiple computers and Exchange.

Anything's do-able, given sufficient time/budget/will.

One simple approach - setup 4x users, where first user forwards to other 3x users.

Then set mail client on 4x different computers to the reply address of first user.

This has the effect of creating 4x copies of each message received.

Envelop From: address then will be then show as first user for all 4x computers.

Thanks David, each computer gets all the same four email addresses.  I don't think that would work.  Unless I am not getting it.

1) You have 4x users.

a + b + c + d

2) When mail arrives for user a (whatever current user is now), a copy forwards to b + c + d.

3) Each machine will run some mail client like Outlook or Thunderbird, with 1x of the a + b +c + d users defined (none of the others).

4) All 4x users will see their own copy of each message.

Note: This is super ugly + likely will cause massive confusion. I would never suggest anyone approach mail handling like this... and... it does satisfy the requirement listed in the question.

Said another way, there's no switch you can flip in any IMAP server to say... Only mark this message as read after 4x unique users read the message... or 4x unique devices access the message... The IMAP protocol doesn't support this type of access pattern, so you must create some oddball access pattern workaround, similar to what I suggested... where you end up with the same message 4x different places.

5) You asked, "each computer gets all the same four email addresses."

Each message on each computer will have a different To: Address (a + b + c + d).

Each mail client will set the same Reply-From address, so any responses will have the same From: address from all users/machines.

Tip: If someone tried to get me to setup something like this for them, I'd urge them to rethink their work flow... as this type of approach to email handling will likely lead to unanticipated complexities.

Thanks David, I'll run it by them tomorow.  

What about deletes, moves and other operations? Do they need to be seen by other users?

The solution to this, although I wouldn't recommend it, is to configure these emails as POP instead of Exchange for the users that don't want to have any sync with what others are doing with the mailbox.

Sorry for the delay guys, getting a zillion people working from home put me worn out.

Qlemo, kinda on moves and deletes, if they loose that I think they will live

Edmond, I think you are right, that’s what I did for now and this may be their solution.

Thanks all.