trigger a video + sound in augmented reality from a certain distance tools - support

Hello community! I am an art student and for my end of study project I realize a digital publishing project with postcards. I recently started using Unity2019.3 0f6 and Vuforia. My question is as follows: Is it possible to display an augmented reality video (+ sound) that is triggered at a certain distance from the paper medium?
When my phone is less than 20 cm from the paper, a video is triggered. When my phone is more than 20 cm from the paper, another video is triggered.
I am not a developer so if someone could help me I would be very grateful!
Thks