property returning a reference vs returning a value

[cal]

This doesn't compile, because the assignment matches both 
property functions in S:

struct S
{
     @property int a() { return _a; }
     @property ref int a() { return _a; }
     int _a;
}

int main()
{
     S s;
     s.a = 5;
}

But I would like to be able to do different things when I pass 
out a reference to _a compared to when I just pass out the value. 
I also don't want to require an argument to the ref property 
function. Is there a way to do this?

Thanks,
cal