What's a Good Way of Automatically Assigning a Clearance from a Plane to a Pin or Class of Pins?

Just an overview, I have some though-hole pins on the bottom layer that are high-voltage. On the top surface is a huge polygon or plane designated as GND. On this GND plane, within the vicinity of the high-voltage holes, I wanted to specify a clearance of let's just say 100mils (to avoid arcing from the high-voltage pin to the GND plane).

At present, I manually added to the high-voltage pins some isolation/cavities on the polygon/shape assigned as the GND. This works for now because I have few pins. But when the number of high-voltage pins (and traces or other components) increases, manually defining the isolated areas become impractical.

So my question is, how can we do this automatically at Orcad PCB Editor (v16.6)?

With Altium Designer, I can simply add rules and create SQL-like statements to define that high-voltage pins should always have a 100-mil clearance from any other pin (trace, polygon, and etc).

On a separate question (but somehow related), on the Xsection (for Orcad PCB Editor), when I specify the layer type to be "Plane", I don't seem to see any difference on the actual layer when compared to the layer type being set as "Conductor". On Altium Designer, if a layer is specified as a plane, a polygon covering the entire layer is automatically defined which you can set to any "net" (for example GND). On Orcad PCB, when I set the layer to a "plane", I don't see anything unique happening on the layer. I can still add any shape to this layer like it's a "conductor" type of layer. I may be overlooking something here.