Connecting objects without affecting layout

I have a diagram that uses auto-layout (radial). And I want to add extra lines between objects without affecting the auto layout—e.g. the dotted line in the attached image:

But auto-layout considers these to be hierarchies and changes the layout. Is there a way to exclude some lines from what auto-layout looks at?

Not really, but there is a workaround.

Make sure connected objects is your scope in the Diagram and Layout Style Inspector.

Then, when you make your dotted line, turn off this checkbox so that your dotted line is not actually connecting the objects.

I hope this helps!