Enable/Disable field values based on another field's value
I doubt whether it is possible. You cannot hide certain radio options in a radio group. It is the whole group or nothing. I will look rather at a custom jQuery solution coupled with a server-side validation method.

The jQuery will have to:
display all hidden radio options in destination, then hide the corresponding radio option in the destination when source is selected. You will have to add the jQuery to the page via  hook_preprocess_html or something similar, or use the module JavaScript Libraries Manager.

Server-Side:
You can use the Field validation module. Put the validation against both fields, and use 'Equal values on multiple fields', and set it to reverse.