suppose if your model has a constant block whose value you want to set depending on the radio button, then in the callback of the radio button you can put a
for eg: Under call back of Radio Button 1
if hObject('value')==1
set_param('Constant Block Path','value',1);
end
similarly Under call back of Radio Button 2
if hObject('value')==1
set_param('Constant Block Path','value',2);
end
