Yes, you can store multiple email addresses for a single user. First, go to the person’s profile. Then, enter the additional email address(es) separated by a comma and a space in the appropriate field. For example:
firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, etc
Then save the profile. Now, whenever an email is sent to this user, it will be sent to all of the addresses listed on the user’s profile.