Event Regsitration using rental fields

I have a big event to create a registration page and form for. We are using "rental fields" for the timeframes (example 12:00-1:00pm) and then each session within that timeframe will be a value (session ID) in that same field. From there, I have a smart campaign that is looking for a data value in that rental field "containing" the session ID to pull them into their perspective event programs. I've tested what would happen if someone signed up for multiple sessions in one time frame and it isn't working as expected. I believe its because the values are being stored with";" at the end of the session ID. How can make sure this doesn't happen? Ideally, we don't want people to sign up for multiple in one timeframe anyway so is there a way to block them from doing that or at the very least, can we have them get pulled into all programs?

Here's any example of the form (the form won't show on the page like this so don't mind the non-stylized/complete version. This is only for testing) 

Here is the smart campaign:

Here is my record. The only event that registered was D1-DA-04 because didn't have a ";" at the end.