Email Passcodes For Makeups And Remakes

This is the first year we are using import passcodes with emails. They worked fine for the regular student portraits. 
The problem is the makeups (students who were not photographed the first time) and remakes.
I made the jpgs with the pascode with emails for the makeups and remakes, but I would like to be able to send out a passcode email to ONLY these parents. I want to add them to the same gallery as the original pics so all the images are in one place.

Is there a way to clean up the email addresses so it will only email the ones from the last passcodes file added?

There is not a way to do that. Maybe you can create a new gallery for those photos and then email them from that new gallery.

Could you re-import the passcodes with the new subjects (athletes/students) added? Then could you send emails with passcodes to those who haven't accessed their photos/placed an order?

As of the last update, you can now check the checkboxes next to the entries you want to send an email / passcode to.