Simple sequence drag and drop

I want the learner to be able to rearrange a list within the same list [ie not by dragging to another place], so that the other items in the list automatically rearrange themselves around where the item is dropped.  The numbers down the side are to remain in place.  There is no correct answer and no feedback, as it's asking the learner to provide their own ranking of the items.

First, am I correct that there's no pre-built option in the Custom Library for Storyline 360?

If not, how do I write triggers so that the drag, drop and rearrange function works?  Or surely there is another simpler way?!
I've attached the basis for the slide - the layer is for a follow-up exercise and not relevant to my question.
I'd be so grateful for help on this - it's a really useful interaction with the learner.