Targeted UI/ or HA to HA communication

This is for an assistance calling system for a motel. There are 50 rooms and 7 service provider (Laundry, Restaurant, Chef, Room Service, Chauffer, Reception). Each of the room has a KNX based touch screen where they can access these. Once they press this, it should alert each department and if some one acknowledges this, that particular user should be able to see that it is acknowledged and help is on the way. How can I do this?

Is there a way to display UI based on which device (IP or MAC Addr or URL or POST or GET or USER) it is called? I have a RasPi running centrally that communicates to KNX interface. I have 7 different tablets fixed at different rooms, depending on the which room the tablet is called, it should show the status at only that ROOM. Groups are great but i can swipe to other rooms (it should not happen) Also I would like to have client-server architecture in terms of the ability to display. Like notifications only sent to one particular device and only that device should see the notification. This notification is actionable and once the user actions, the message must be sent back to the another device. Is HASS the wrong product for these prupses.

In the event the above is not possible, I am willing to run 7 RasPi. However only one of the Raspi will be interfacing with KNX. How can I therefore communicate and read status between RasPi/ HA.

Not completely sure of your purpose here but MQTT may be what you want.

MQTT allow message sending. You can choose message format and data.

FOR EXAMPLE

Room 1 UI has button for laundry, room service and operator.
Push [operator] button message sends

TOPIC: Room1/request
DATA: (room, 01, temp, 80 , laundry, 0 room_service, 0, operator, 1)

Any receiving device can be setup to display this and Automate action based in this data. Many way to accomplish this and many way to structure data, this is just example

So the receiving device should have Home Assistant?