Thank you for your comment, Shawn; as you mention, Matlab already has a hash table built in: the containers.Map class. They make it difficult to find by never mentioning the term "hash table" in the documentation.
suplabel
Places text as a title, xlabel, or ylabel on a group of subplots.
Author: Ben Barrowes
The problem with zooming is that suplabel places its axis on top of all other axes in the figure. You can fix this by adding the following lines under the
ax=axes('Units','Normal','Position',supAxes,'Visible','off');
line: