The way I did it was:
I asked 3 villagers to follow me and when they are standing altogether; I turned off safety mode and the best weapon I used was the
Enforcer.In case some of you do not know where the
Enforcer is, here's the location for it:-
http://fable.wikia.com/wiki/The_Enforcer Many thanks for Fable wikia for the info.So basically it doesn't have to be enemies, it also counts for incconent people as well.
EDIT #1 Instead of having 3 villagers following you, it is wise to have 10
to follow you. (this saves you time in case if you mess it up and
reload the game again)
Thank you to ninja277 for the heads up.EDIT # 2 MUST HAVE LEVEL 4 ACCURACY. You can hit 5 guys (and I have) with one shot and kill all of them and still not get this. Level 4 accuracy is a requirement it to unlock this.
Thank you to ArmedJet Stream for the info.Before you give me a negative vote, please explain yourself why you did it and I will be more than happy to improve my solution. Thank You.