I have a Sharepoint list where users create items and assign them a priority. These items are all orders that are stuck in our system. By request, the priorities are all multiples of ten and unique.
However (as was always going to happen!), as the list got bigger, more and more of these unique values have been taken. I've now been asked to make the values only unique if the items have a status of Open (rather than Closed).
I know I can do this by creating a workflow and transferring everything that is set to Closed to a new list, without the unique constraints.
But I'd rather keep it all in one list, if that's possible.
Is there a way to do this? I tried experimenting with list-wide validation settings, but there doesn't appear to be a "ISUNIQUE" or something equivalent to it.