Social Golfers

Hi there,

    I'm using Eclipse 5.7. I've been implementing a number of different 
models of the social golfer problem in Eclipse. I've run into a problem 
in trying to
implement one of the constraints for a particular model I have 
formulated. The code I have written so far is:

% Give an account of this model in mathematical notation. C1 and C2
% are automatically enforced my the setup of the data-structures in
% this model
sgp_model2(Weeks,NumberOfGroups,GroupSize,Groups) :-
    % Calculate the number of golfers
    NumGolfers is NumberOfGroups*GroupSize,
   
    % 2-d Groups Matrix of Variables
    dim(Groups,[NumGolfers,Weeks]),
   
    % The Domain of each Group matrix variable is the range of
    % 1..NumberOfGroups
    Groups[1..NumGolfers,1..Weeks] :: 1..NumberOfGroups,

    % C3: limits the number of times a group identifier appears in a 
particular
    % week to GroupSize
    (for(W,1,Weeks), param(Groups,NumGolfers,GroupSize,NumberOfGroups) do
        (for(G,1,NumberOfGroups), param(Groups,W,NumGolfers,GroupSize) do
            Occur is Groups[1..NumGolfers,W],
            occurrences(G,Occur,GroupSize)           
        )
    ),

    % C4: All pairs of golfers must play each other at most once
    sigma(W)(Groups[X,W] = Groups[Y,W]) <= 1

   
I cant seem to represent the last constraint (C4) the way I would like 
to in Eclipse. I was hoping someone could show me how this is done? The
notation I've used some summation over a range of weeks might look a 
little odd but it is just to ensure that no golfer plays any other golfer in
the same group more than once.

Thanks in advance,
Mark.