There is an attribute rule regarding elevation, but it concerns tying a Pipe Connection's elevation to that of the Catch Basin. In my case, I am snapping the Gravity Pipes to the Catch Basins. This means they are connected via geometric coincident based connectivity, so while it seems I am changing the z-value for one feature, I am actually changing the shared vertex, which is why it updates the geometry for everything else that is connected. Is there a way to change the connectivity in a way that they can share the x- and y- values but not the z-values?