Making a "required" field gray or read only will not disable the "required' property. You need to adjust this property for the fields for the options not selected.
Sorry, I don't think I understand, what do I have to adjust exactly? What properties?
The radio button group has a value. When no button is selected that value is "Off". When an individual button has been selected the value for the group will be the option or export value for that individual button.
>> Also, I have the radio buttons for the three options setup so that if the user holds the shift key and clicks a radio button, it unchecks it.
Radio button in a PDF do not work that way. Only check boxes can be unchecked by clicking on one that has been checked.
If you plan the coding for the Mouse UP action to test for all possible options and code for each of those options you should have what you want.
If you want actual code you need to provide a lot more details.