individual object menu

Hi All I have this idea to make an object (eg. A buidling) have a menu(GUI buttons inside a box) when you click on it the menu will show up right next to the object with a list of buttons inside a box but will I have to use mouse position or use the objects position and set the center off alittle?

And if I can do that would you help by presenting me with a example script because I only know enough to edit scripts not create them all on my own :/ please help me ?!?