In LV10 I use the Move Selected Objects Method of the TopLvlDiag Class (ie. Block Diagram). I use the Joints[] property to find the segment I want. Typically I index the array to select the starting joint. I will use the maximum of the Left/Right/Up/Down indices to find the opposite end of the segment. Using those two points I would use the Point2Rect.vi followed by RectCentroid.vi (both in vi.lib) to find the center of the segment, and then use Point2Rect.vi again with the incremented and decremented centroid value. This defines a very small rect around the center of the wire segment. Then I would use the Clear Selection Method (TopLvlDiag), followed by MakeSelectionFromRect using the rect you found, followed by Move Selected Objects with appropriate Delta X/Y. Finally Clear Selection.
I could post an example later, this is from memory. Better learning experience recreating it yourself. I have added other features like finding the segment closest to a given point, and double checking that the selection process does not add other objects. It is easy to get the terminals selected on shorter segments which are hidden.
My other point is that you are usually a much, much happier scripter if you let LV deal with the wiring (BD cleanup, Clean Wire method, autowire). Futzing with wiring in scripting is a spaghetti factory, this simple task is already a screen wide on a BD.