The way I do it is with different keymappings for each character.

I use [ins] and [del] to step my /follow characters apart from each other.

char1: strafe left: [ins]
char2: straft right [ins]
char3: backwards [ins]
char4: forward [ins]

That way when I press [ins] the four chars that follow my main each move in a different direction in a roughly diamond pattern. I have bound [del] to the inverse movement direction on each char, so I can move them back as well.