Your script can modify a value in a global variable or a field. Your conditional formatting (and Hide Object When in FileMaker 13) can then use expressions that reference the value of that field or variable.
You may find that you then need to give the layout text an object name in the Inspector and your script would change the field/variable value followed by Refresh Object to refresh just that one layout object.
Thanks very much for the ideas ... I knew that there must be a way but not smart enough to figure it out. Really appreciate the guidance. Just one question: when I give the tab a name in the inspector, is that considered an object name?
Yes, that is an object name.
You may find that you then need to give the layout text an object name in the Inspector