…such as the one attached.
Looks like I can not embed attached image.
You can right click on the header of the state and select Add Horizontal Region to insert the region for a state (see attached pic). After that you can right click on the state and select Add Region to insert more region in the same direction. The separator (dotted line) will shows if the state contain more than one region. You can embed other states and transitions into the region once you created it. Feel free to contact me if you require any further information.