I have had the problem with customers on relying on wires with multi color for identification in their system. It would be good if Autocad could implement the possibility for multicolored wires. Today you can use multiline for this visually, but it would be nice to get the functionality of the wires. I hope you make it possible and it should not be much work to put this in an update.
Many of the customers have gone away from labelling the wires due to cost and a hassle with marking high temperature systems or systems exposed to bad conditions.