Consider draggables elements with same index as a one-draggable-block

A list of draggables have a continuous incrementing index. In my case, some consecutive elements are consider a block, so it would be great to assign them the same index, meaning they all drag as a block. Also other elements can be dragged before or after the block, but not in the middle.

I tried to do a codesandbox to show the case (obviously it does not work):

https://codesandbox.io/s/520y4687xx