Color Coded Officer Lines.
Perhaps a way to settle some of the confusion in game is to introduce color coded lines in the line draw tool. Say each of the two (soon to be 3 maybe) regiments lines are given a standardized color. Example 1st = White 2nd = Red 3rd = Aqua blue. When an officer from that regiment draws a line the men in that regiment will know it is orders for them because it is the color they know is assigned to their officer. This would make it easier to divvy up a team among the available regiments.