Hello James,
I just spoke with development, and this is not currently on the list for the next release of Dynamic Forms. There were many other items in queue before this was suggested.
If you're unable to wait for this feature it would be possible to achieve via Premium Support if you needed this for a custom solution. Here's a link to our premium support:
http://www.datasprings.com/Premium-SupportPlease let me know if you have any questions.
Thanks,
Ryan