No.

|So, is there a way to easily resolve this issue with
|an alias setting for each user that will carry across
|lists?

TRAIN your users to pick an email address and stay with it.

I mean why would any mail system equate [log in to unmask] with
[log in to unmask] and not [log in to unmask] ?

These same users are going to get a reality-check when they start
complaining to external postmasters/listowners about why they can't post
to those external lists.

/Pete