Wireless Intercommunication (Notification sys)

I work with kids in a Mental Health office and I need a system where I am able to notify a clinician (via wireless comm.) that their client has arrived, without interrupting session.

We currently have to either call the clinicians or knock on their door to let them know the next client has arrived, both causing an interruption in session. I want to avoid that interruption, so which is why i am looking for "something" that can visually notify the clinician (e.g. a green light being switched on or pulsating light) The light needs to be subtle, where the client won't be distracted, but emitting enough to where the clinician can see peripherally.

No need to exchange any sort of personal data (client info) just for a light to be turned on and able to be turned off by clinician at request (push of a button)

If i could get some help, please.

thanks in advance.

Would something like a doorbell notifier for the blind or hearing-impaired that blinks a small light attached to an electrical outlet be sufficient? http://www.amazon.com/SadoTech-Flashing-Vibrating-Transmitter-Operating/dp/B00P90X4CM/

The technology for this pre-dates the Arduino somewhat . . .
servantNotificationSystem.jpg

servantNotificationSystem.jpg

thank you guys, i'll try to work w/ this.