Creating a new primitive

Hey,

as i need to a simple but tedious task dozen of times i want to utilise maxscript to do the job for me. I need to show measurements of certain areas by displaying the actual size in 3d text, a rectangle shape and 3d arrows within the 3d scene. My goal is to make these 3 things into one primitive which has animatable parameters (width, height, distance offset) . What i would like to do is to extend the rectangle shape object so the 3d text and arrows change accordingly to the width and height parameters of the rectangle object.

Problem is, i dont quite know how to do this. Im new to maxscript so if you could give me some pointers on how to accomplish my goal, that would be great! I already watched the maxscript 101 video tutorials and understand them but i cant translate the knowledge in those tutorials to my problem.

Any help is appreciated! In the meanwhile, ill try to keep learning maxscript and hopefully i can make this myself.