"I have a situation where one device may be used by several people whom I need to monitor. I plan to connect the Traccar client application with the XYZ application on my device. When logging into the XYZ application, the username would serve as the device identifier in the Traccar client. Is this possible? If not, do you have any other suggestions or solutions that I can implement?"
Sounds like you need to custom Traccar Client anyway, so it should be possible if do in the code.
"I have a situation where one device may be used by several people whom I need to monitor. I plan to connect the Traccar client application with the XYZ application on my device. When logging into the XYZ application, the username would serve as the device identifier in the Traccar client. Is this possible? If not, do you have any other suggestions or solutions that I can implement?"