How to align a user account (< 9 characters long) to a specific AD domain?

How can I align a user John.Doe to one AD Domain, and user Jane.Doe to another AD Domain in the same forest?

Have tried using the winbind separator ex: domain1+jdoe, but long Domain names and long user names get messy.

Authenticating john.doe@domain1.forest.net from jane.doe@domain2.forest.net with previously setup UID and GID is the challenge.
Dont want auto-created accounts.... just the password authentication to non-cached (if possible).

In short, can I map:
jdoe1 to john.doe@domain1.forest.net
jdoe2 to jane.doe@domain2.forest.net

Ideally, one would login as jdoe1, but it might also be acceptable to login with the UPN (john.doe@domain1.forest.net), provided that the short name (jdoe1) would appear in system output like 'ps -ef ".

Thanks for your thoughts.