Shared Params Multiple Files

Hello,

I'm trying to do nonlinear fitting with shared parameters (also known as global fit). I do have 5 data sets of varying x,y. Thus z would have only 5 values. My fitting function comprises of 5 parameters and looks like this (when used for only one data set):

% Set up fittype and options.
ft = fittype( '(a*x^b)/(c^b+x^b*(1+^b/d)+z/e)', 'independent', 'x', 'dependent', 'y' , 'independent', 'z');
opts = fitoptions( ft );
opts.Lower = [0 0 0 0];
opts.StartPoint = [0.0004 1.2 0.7 1.4 0.003];
opts.Upper = [10 10 10 10];

Do I need to have the data (ie.x1,y1,x2,...) saved as separate variables or I can put the data in three variable sets x,y,z and tell the code to work with columns? Could somehow make a code that that would enable data analysis in

cftool?

I'm really confused, hope my question makes sense. Thanks a lot!