Unable to create terrain wall of different heights

[ptr727]

Hi, I am trying to add a wall around three sides of my property.

The back section is 8' tall, the front yard sections are 3' tall.
I draw a straight terrain wall on all three sides.
I set the height to 8'.
I try to insert a break in the wall, nothing happens.

I create disconnected sections.
Set the two different heights.
Draw them to connect.
The entire section becomes one wall and reverts to 8'.

I'm using Pro 2014 5.2.1.3x32.

Any ideas?

P.