return all models to original location (image target)

hello,

currenltly I'm making this augmented reality app, using vuforia. As many of you know, an AR camera asset tracks the image target, and projects anything you want on it. so far, so good. (im working with an assembly of a pump)

as I wanted my AR app to be interactive, I added some functions like 'lean select, rotate, scale, translate and fingertap'. this works completely fine. so I can translate, rotate and scale all parts of the assembly in my app, but I cant get them back in their original place, rotation and scale properly...

how can I, by the push of a button, let all the parts (drift) back to their original position, rotation and scale ? (on the image target)

thanks!