Well, it depends on what you consider undesirable. There are two things that you can do, one in the template and one in the admin.
In the template you can get the value of the radio field and then get the correct address field based on which is selected. This would be my preference since it requires the least amount of extra code.
In the admin you can create an acf/save_post action http://www.advancedcustomfields.com/resources/acfsave_post/ and in this function you can see what the value of the radio field is and then delete the contents of the other field.
