How can I express this triple sum objective function in CVX?

How can I define the variables express this in CVX.

\min\sum_{g=1}^G\sum_{i=1}^{N-1}\sum_{j=i+1}^{N}d_{ij}z_{ijg}

Here, d_{ij} are known and z_{ijg} are binary integer variables.

I define the variable as

            variable Z(N,N,G) binary

But not able to express the objective function.

You are allowed to use as many levels of for loop as you wish.

First formulate what you want presuming that Z is a numerically populated MATLAB double precision variable. Once you have done that, it should work when Z is instead declared a MATLAB variable. Any vectorization you do is a speed bonus, but not needed for correctness.

Thanks. For now speed is not an issue. I just want correctness. Do I need to define an expression to be able to put as objective, as I cannot put nested for in the objective?

Before for loop
Objective = 0; % no need to declare Objective as an expression because it is a scalar.

Inside for loops:
Objective = Objective + something;