Multiple touch event

Hi All,

I’m developing something like piano where there are several different objects in one screen and it should play it relative sound when some one touches it.

My Question is:

Can I put Single screen with  all object embedded init (No layers only image) and have different touch events according to the co ordinates ?

or

Do I need to add all objects with touch events on a background screen?

This architecture should work for any screen size(different devices)

Sudheer