Drag and drop lists – multiple items with same priority

Initially, I had the following requirements:

1. There are 2 lists with items. The user needs to be able to move the items from one list into the other.
2. Each item needs to have a priority.

I've implemented the following solution:

The user can drag and drop the items and I'm also keeping track of their priority. For example, in List1, Item1 has priority 1 and Item2 has priority 2 and so on. In List2, there is just Item4 with priority 1.

So this solution covers all the requirements.

The problem is that now there is a new requirement: multiple items can have the same priority.

So I can have Item1 and Item2 with priority 1 and Item3 with priority 2.

Can this current solution be adapted to this new requirement? I did think about it but wasn't able to find a solution.

Or is there a completely different approach that is more suitable?

Thanks!