Yes, you can have multiple programs active, at the same time, in your EZ Tally database.
This allows you to keep mileage separate, based on event/club/group.
For instance, you could have an after-school run club program, a program that tallies all the students during gym classes, and a fundraiser walk-a-thon program, all set with the same or overlapping start and end dates.
If you have multiple active programs, you will be asked to choose which program the laps will be synced to when you start a scan session in the EZ Scan app. You can scan laps to only one program at a time, per scan session, per device.