I'm not 100% sure I understand.
But if you mean that a group of draggable - which are all in the same container - should not register overlaps, then the drop option of event.drag is how you'd do that:
drop (Boolean|String) Default: TRUE
A boolean to indicate whether or not "drag" events are considered in the drag interaction, or a jquery selector expression that should filter and match a subset of the registered drop targets. (FALSE = No Dropping, TRUE = Drop Anywhere, ":expr" = Drop in targets that match this expression)