You can set distances for attack in the enemies script file. If you look at the script files for varying enemies you will see how their attack ranges are set up differently.
If you mean melee attack then FPSC enemies do not support that by default and you would have to make a model enemy with appropriate animations and get it into FPSC - If you can do that I see no reason why you then could not get that enemy to attack at close quarters.
I would suggest that you do it the other way around and set up a test character first from copies of a default enemy and learn how to amend the script to get a close attack working - close enough for your needs - thats the easy bit - the new models the hard part.
Sorry I have no idea if melee attack will make it into V1 or any future version. If it does then maybe TGC will supply an enemy with appropriate melee attack animations and supporting script file.
Unless I am incorrect, scripts are actually limited by whats in the engine hard coding. If the engine dont support it you cant do it. It can certainly do what you want in this case.
