Built into the touch and mouse objects are "On-object-touched" or "Is-touching-object" and "On-object-clicked" or you can do a Mouse-button-down&Cursor-over-object condition.
Or you could use an instance variable inside all your objects for IsSelected=0 and change just the selected object to IsSelected=1 when you want it to be controlled and toggle off when out of control... your control events would just need to condition for "IsSelected=1".
Thank you chrisinfinger,
Ok, in this case the "Control" buttons in the layout will look for an object which has the variable "IsSelected=1" to apply the action on it.
So, the question is: Should all objects be evaluated to know which one has the variable "IsSelected=1"???