Best Approach for this scenario

I have an image and video dropdown based on which the following field for video or image link is displayed.. I have a requirement to save the value from the selected field to a single property in jcr.

i.e If the video was selected the link property should be video link and the next time when the image is selected the link should be updated to image link. 

I have a sling model using which this data is exposed as json and final json should have only one value for the link (image or video) .