Compressed code:
for(%x=0;%x<ClientGroup.getCount();%x++)
if(isObject(%p = ClientGroup.getObject(%x).player)
%p.kill();
Easily readable code:
for(%x=0;%x<ClientGroup.getCount();%x++)
{
%cl = ClientGroup.getObject(%x);
%pl = %cl.player;
if(isObject(%pl))
%pl.kill();
}