Add ability to automatically identify/color code duplicate item names within a board

[RLMyrick (Rebecca Myrick)]

My team creates control numbers to identify documents. The control numbers are the “items” in our board, and each needs to be unique. The control numbers are determined by the users, entered manually, and assigned in order, so it’s easy for people to repeat a number if they’re entering numbers at the same time as someone else. I would like a way to automatically and immediately identify for someone if an item name that they’ve entered is not unique. Color coding via conditional formatting would be a perfect solution, although I’m open to anything that works, as long as it happens automatically whenever an item name is entered or updated.