Add/remove a div and reorder after insertion or deletion

Using jquery sortable lists, I am able to create a set of divs based on an integer. I.e if the integer is 4, I create 4 divs: div1, div2, div3, div4. I have another div which holds a few items which I drag and drop to one of the four divs (as the example). At the end I get an array of which items are in which div, and the order they are stored in. Now I want to be able to add or remove divs. There should be a small menu in each div which can delete it or add a new div next to it. The tricky part here is that for example, if I delete div2, then div3 should be the new div2 and div4 should be the new div3.