[exim] same domain router to different servers

Hello group,

In the interest of "spreading" the wealth I was wondering if this is
possible:

Could you have 2 (or more) exim servers that handle mail for the smae
domain *AND* each one handles certain accounts?

For instance:

foo.com

server 1:
user1@???
user2@???

server 2:
fred@???
joe@???

When mail is sent to fred@??? it goes to server 2 and if server 1
receives it, it will forward it to server 1 for handling?

Maybe with the same control file on each server:

/etc/vredundant/foo.com

user1@???: 1.2.3.4
user2@???: 1.2.3.4
fred@???: 1.2.3.5
joe@???: 1.2.3.5

Is that even a viable idea?

Then you also have to deal with pop/imap/smtp issues like how do those
services know which server to check...

TIA