How to Group objects within a Slider

You could save the objects as a bitmap, use it for the fill of a second slider and remove this slider's track fill & outline. You can then set both sliders to be controlled by the same variable, so that when you move the first slider, the second one moves as well.

Or, if you don't object to the user touching the object, just use the graphic for the thumb fill and you only need one slider.

Just for fun, here is an example of one slider (at the bottom) "driving" a bunch of additional sliders with bitmaps as the slider thumb (plane, clouds): https://dev.keypointlearn.com/xcl74_SL360/Parallax/V1/story.html 

Thanks for that guys! the thing is that later I would need to use this objects as a "hotspot" so the user can drop another object into it. Here you can see my file, I hope you can help me with that

It appears to me to be working as you describe it.

Yep, Drag and Drop function works fine, but the object (in this case the dotted oval figure) is not linked to the slider position, so right now if you move side to side the slider, the object stays in the same position, and I would really want it to move along with the slider.

Try this. There are two slides, one using states, and one using motion paths. Only four of the motion paths are complete, because they are a lot more work, and I got lazy. I think there are enough of them to give you the idea. The states are 86 pixels apart.