Hi Gurpreet,
If you have N users and W weights (where W>1 is arbitrary), then you should create W diagonal NxN matrices. Put these matrices in a row to form one total matrice and the ones in each row of the total matrice determine the wavelengths (for the frequencies) that are used for each user. for example, 0 0 0 1 1 0 0 1 in a row shows that you will have lambda4,lambda5,lambda8 wavelengths for the user relating to that row.
That was a brief explanation, but if you want you can easily google it and find plenty of useful links on it within seconds.