Overloading operators, multiple assignment e.g. a=b=c

Question

I am having trouble finding a way to enable the assignment operator to do multiple assignments.

given that there is

item A,B,C;
for(int i=0; i<10; i++)
   C.AddHead(i);
A = B = C;

for a single assignment

item ::operator=( item &copy)
{
    ...
}

How do i write the code for multiple assignment like

A=B=C;