In the editor, place down any amount of units you would like form the same faction. Two would be easiest. Make sure one unit is a team leader and the other is another non-leadership role unit. Make the player the non-leader unit. Once in the game, you can use the "`" or "~" key to use the option "switch to leader".
Once switched to the leader, you can instruct the AI as you please, but it will glide around in whatever stance you left it in. Potentially, you could have an entire squad of snakemen.