Assign the Time Sync configuration to a site specific folder and then either manually relocate devices between folders when they change physical location or use Relocation Rules based on IP to automatically move them. 

As you should be using Zebra devices with rich MX commands and OEMConfig parameter supported for AE devices,  You can likely find the way to enable automatic time settings options, or setting the device to use a specific time-zone.  The remaining issue is how to have it done automatically.

If you have GPS hardware enabled, you might also consider implementing geofence alert rule to automatically relocating device to appropriate device group corresponding to the right time zone.  Then, depending on the device brand/model, enrollment mode and scripts/OEMConfig-parameters supported, you might have appropriate script or Android-Enterprise OEMconfig parameterization to change the device time-zone upon such relocation.