I'll generally set up smelters to have bills along the lines of "smelt all biocoded weapons", "smelt all tainted weapons", "smelt all tainted armor", etc. When there's a lot of work to be done, this often results in pawns running around to collect all tainted weapons before all tainted armor, for example, based on whatever the priority order is, even if there is tainted armor right next to them. It would be fantastic if we could mark multiple bills as equal priority so the standard shortest pathfinding algorithm can let them tackle the bills in arbitrary order.