Hide Email for Specific Users in Directory

We have a lot of location based 'users' aka "X-Ray Tech Area" but there is no actual email for this 'user' as multiple x-ray techs will be using this phone. In order to create a user, an email is required so generic emails are used, but these aren't always necessarily real emails or the correct emails. We'd like 'X-ray Tech Area' and their extension and external line to show in the directory, but not the generic email address used to activate the extension.