Control port entry/exit direction in RectilinearEdgeRouter?

Hello,

I have a graph of nodes containing 'input' and 'output' ports, and I'd like to use the RectilinearEdgeRouter to route the edges. I have a basic version of this working

var rectRouter = new RectilinearEdgeRouter(this, 10, 3, true, true);
rectRouter.RouteToCenterOfObstacles = false;
rectRouter.Run();

However, I would like to ensure that edges always connect to inputs/top-ports by going 'up' and to outputs/bottom-ports by going 'down'. Or perhaps in other words, I would like to minimize, or ideally completely prevent edges overlapping with nodes...
You can see an example of how it looks like without this constraint below. I browsed through the code and directions seem to be handled explicitly, so I believe this should be tweakable, I just don't know how to do it...

Start by reading the RectilinearEdgeRouter entry point and the direction-handling code mentioned in the issue, then reproduce the provided routing setup. Trace how port sides and obstacle avoidance are selected; done means input/top ports route upward and output/bottom ports route downward without edges overlapping nodes, with coverage for the behavior.