Help with New attack I want to implement.

Hi, I've been wanting to change the way how the attack system works in ISK. I want that when i Click Ctrl + Mousebtn0 to a target, if it is melee weapon, It will automatically go near and continuously attack the target, and if it is a long range weapon (Crossbow), I want it to be hitting the target without the mouse having to be pointed to the target for it to be able to hit it. In short, I want a normal MMORPG way of battle system with weapons. Can someone help me? Thanks. Pointing me out to a resource would be much appreciated or if there is none. Help me please. Thanks.