Controlling of two subplots by one slider

I would like to kindly ask you about slider controlling of two subplots. I have the following variables containing 3D structures with five images:

a(:,:,1)=rand(300,300);
a(:,:,2)=ones(300,300);
a(:,:,3)=zeros(300,300);
a(:,:,4)=5*ones(300,300);
a(:,:,5)=zeros(300,300);

b(:,:,1)=zeros(300,300);
b(:,:,2)=ones(300,300);
b(:,:,3)=zeros(300,300);
b(:,:,4)=ones(300,300);
b(:,:,5)=zeros(300,300);

The variable a shall be placed into subplot(121), and variable b in subplot(122). I need to create one figure containing these two subplots, and one slider simultaneously controlling both subplots. I have done implementation for one series of images:

b(:,:,1)=zeros(300,300);
b(:,:,2)=ones(300,300);
b(:,:,3)=zeros(300,300);
b(:,:,4)=ones(300,300);
b(:,:,5)=zeros(300,300);
smin=1;
smax=5;
hsl = uicontrol('Style','slider','Min',smin,'Max',smax,...
                 'SliderStep',[1 1]./(smax-smin),'Value',1,...
                'Position',[20 20 200 20]);
set(hsl,'Callback',@(hObject,eventdata) imshow(b(:,:,round(get(hObject,'Value')))))

I am unable to modify it for two subplots. Please, can anybody show me MATLAB implementation of the mentioned problem? Thank you very much in advance.