Is there a way to add users to a team by associated e-mail address instead of login name?

Given that we cannot make a DTP project public to all users, we may have to consider an alternative approach like managing a user group that contains all users that we will have to manually upkeep whenever there is an addition/removal. In our current testing, we found the search functionality only works if you know parts of the user's login, which may or may not consist of both or only 1 of their names or surnames. However, in our role as the developers/implementers, we may not have access to actual login information to add new users to a DTP team.

Since names by themselves are not unique enough, the next best unique identifier is the e-mail address associated with the user's LDAP account, which is a more accessible field than login information (user accounts inside DTP track Login, Name, Surname, and Email). We also cannot assume user logins based solely on names, so any manual requests for access will need to contain or most likely already contain the e-mail address at the minimum.

Is there a way to add a user to a DTP team by their associated e-mail address instead of their login?