Changing radio button option based on another

In a Mouse Up action of each button, set the value of the other group to the export value of the button in that group that corresponds with the Off or On lable.  Assuming the field group names are EZ-Start and Auto-Trial, and the export values are Choice1 and Choice2, enter the following script in both EZ-start buttons:

if(event.target.value=="Choice1")

{this.getField("Auto-Trial").value="Choice2"}

else

{this.getField("Auto-Trial").value="Choice1"}

Enter the following script as a Mouse Up action in both Auto-Trial buttons:

if(event.target.value=="Choice1")

{this.getField("EZ-Start").value="Choice2"}

else

{this.getField("EZ-Start").value="Choice1"}

Yes, Use a Mouse Up script on both of the "On" radio buttons, to force the other radio button group to Off. 

for example, here's the script for the EZ-Start On button. Note that I'm guessing the field name. You'll need to replace the name in my script with the exact name that is used on your form. 

this.getField("Auto-Trial").value = "Off";