2 cars and 2 same model OBD 2 scanners mixing up data

I have 2 cars and bought 2 same type of OBD 2 scanners. I inserted the OBD 2 scanner on first car and attached it to the first car. Then I inserted the second OBD 2 scanner in the second car and scanned for it and selected it. All the data from the first car got attached to the second car.

The first was no where in the vicinity(wife had to go to home depot) when I was attaching the second OBD 2 scanner.

How do I register the OBD 2 scanners to the respective vehicles?