getting webpart properties of two webparts on one page

I have 2 instances of same webparts which implement ICallbackEventHandler present on a single page.When the page first loads both webparts behave correctly.The issue comes when an event is fired that results in a call back.Both the webparts start behaving the same way like getting the same property values and other stuff .While debugging I found out that even if I place 3 or 4 webparts on the page all of them in the callback event get the same properties as the first webpart.Is there something that I need to do to implement this correctly.It's like using this.title for 3 instances of the webpart on the page gives me back the same value during callback.

Thanks