Quite easy to do.
In your block diagram, right click on the control and select "Create - Property Node"
It defaults to the "Visible" property - which is what you want.
Change it to "write" mode.
Go to the top of your functions palette, and select the floppy disk.
Select one of the "Read File" that matches what your file looks like. Right-click and select help for details on using it.
Read the strings, and use the string compare items to parse them.
Generate a boolean to indicate show/hide and connect it to "visible" above.
Les Hammer