Is there a way to configure CQ5 to use email of users as their username when for logging in to the system?

Hi,

At the moment we use email addresses as usernames (e.g. node names for user nodes) to let users login using their username. But this complicates allowing users changing their email addresses.

Is there a way we can create users with arbitrary names (e.g. user-1) but use their email property as the username for logging in?

Thanks.