Repeat field: Content of one field in template of other field

I have a repeat field with three fields:

  • Preview image
  • file with title
  • description textarea

How can I call the title content from the file field in the preview image template? I want the title of the file field as the TITLE-Tag in the image template. Is where a way to call it like [[+file.title]] or [[+file:title]]?

That’d be pretty cool if it worked. What I tend to do is setting the template for subfields to just its raw output (image URL or text), putting the rest of actual row output in the repeater template.