Hi Concetta!
Generally, once they reach capacity, the races will not open back up for new registrations. However, if you look on the
Tower of Terror 10-Miler website, there is some information on the right side (bulletin board) about how to register for it as part of a charity or travel group. That could be an option.
Sometimes, runDisney will be at other race expos and offer limited registration for races that are closed, but that is usually decided last minute and as of now, there are no plans to do that for the Tower of Terror race.
You definitely want to "like" the Run Disney page on Facebook. Sometimes they will announce special things like that on there, so it would be a great way to find out if any spots became available for any races.
Please let me know if you have any other questions about runDisney! I am really excited about the Tower of Terror 10-Miler. It's going to be a great race!