Fixed Value in Ref (Name)

[Yeyo1976]

Hello, I am trying to develop a simple two-way communication system, between parents and teachers. I don't want a chat. 

This is my table structure

And  in "Nombre Usuario"

The form has this structure

When I click in the "Apoderado" it shows the children associated to his parent when I select the "Apoderado" 

What I need is that if the "Nombre Usuario" is that of a "Apoderado", it only shows the name of that "Apoderado", not the complete list of all the Apoderados enrolled in the course. It must be considered that if the person who begins the communication is a "Profesora", she does have access to all the course Apoderados.

Thanks!!!

[TeeSee1]

https://support.google.com/appsheet/answer/10106620?hl=en

[Yeyo1976]

Hi, thanks but this is not what I need.

This is what I do it in the last two drop-down list.

I need that the value Nombre Usuario works as a ref in the next field without the user select that option.