Yep, I solved it using ROS. Rather use ROS vs Laravel Echo since ROS does async multi node communicate natively where with Echo, we would need another 3rd party library (Redis or Pusher). Hate using libraries when it may not be needed. (BTW we chose Laravel and jQuery because 5.5 has a 5 year LTS and jQuery just works and easy to pick up as we scale. Vue, Angular and others are just moving too fast. Been on projects where so much time is lost with versioning hell).
I recommend playing with ROS and ROSlibjs. The ROS architecture is incredible.
Back to the solution: How we have it set up is nice - we just make a service call with the userID and a ROS topic gets updated with the userID. All the other computers listen in on the ROS topic, grabs the userID and logs them in. When the user moves away from the robot within a certain distance, they are logged out. Simple, happy robot.