OS X: Always have an app open at specific location in the Dock, without permanently keeping it in the Dock? Let's say, I sometimes want to use Application XYZ, but I don't want to set its Dock Option to Keep in Dock so its icon is visible at all time.

When I want to use the application, I open it with Spotlight. It will open and place itself to the right end of the applications in the Dock. 

I would prefer it to lie closer to the middle.

Is there a way to place it at a specific location permanently, without having to always keep it there, regardless of whether it's active or not?
No. Apps that are not kept in dock when opened will be positioned at the end of the dock.