kinda like the hotkey chat commands in many modern first person shooters?
I interpret your idea as, press 1 to select a group of soldiers (ranging in size from 1 to "X") (where X is the max size of your group) 2 to select a different group,
press 1. Your character shouts "ARCHERS....."
press 3, Your character shouts "...CHARGE!!!"
This would necessitate completing a command before you could order a second group.
press 2. Your character shouts "AXEMEN....."
press 1, Your character shouts "...STAND YOUR GROUND!!!!"
If you were going to do something like this, it would require a more robust party control system wherein you could assign specific soldiers to specific roles.
I can't help but think that I'm not quite on the same plane of thought as you just yet.