Assuming the three surfaces are on the same axes, you can set the cdata for each surface. The cdata can be normalized so that each surface shares the same range of cdata values. Then set clim to that same range to ensure that the colorbar shares that range too.
% Create zdata for 3 data sets
[X,Y] = meshgrid(1:0.5:10,1:20);
data1 = (sin(X) + cos(Y))*6;
data2 = 5*peaks(20) + 100;
[X2,Y2] = meshgrid(-5:.5:5);
data3 = (Y2.*sin(X2) - X2.*cos(Y2))*4 + 200;
% Compute cdata for each data set so that it ranges from [-1,1]
cdata1 = rescale(data1,-1,1);
cdata2 = rescale(data2,-1,1);
cdata3 = rescale(data3,-1,1);
% Plot each surf, specify cdata
figure()
s1 = surf(data1,cdata1,'EdgeColor','none');
hold on
s2 = surf(data2,cdata2,'EdgeColor','none');
s3 = surf(data3,cdata3,'EdgeColor','none');
% Set color range to the range of cdata
clim([-1,1])
% Expand aspect ratio to better see space between surfaces
ax = gca;
ax.PlotBoxAspectRatio(3) = 2;
colorbar()
