Zooming without moving camera

Hello guys, I am creating an application for android in which I use isometric view having the camera fixed in 3D scene. To make some menu buttons some objects always need to be at the side of my scene , and their position should change accordingly to camera. in order to create zooming event on android, is this possible to change the positions all of the objects of the scene except those menu buttons accordingly to camera position instead of moving camera accordingly to theirs? This means that I want to zoom into objects but I still need those menu buttons which are also some objects in the scene to stay at side of my display. Any better idea to do so?

Either make your GUI as GUITextures, or if you have 3D poly stuff for the GUI, make a second camera that only renders your GUI elements infront of the game area (by assigning a layer just for them), and have the game area rendered on its own by another camera and zoom with that.
Don’t scale the objects as that will brake stuff like batching.
Just change the “size” value of your iso camera.