How to show view available in viewStack

Hi,

I have a 4 views and 4 buttons.

when app start only one view in stack

viewStack : ["VIEW1"]

when we click button "open view 2"

viewStack : [ "VIEW2", "VIEW1" ]

when we click button "open view 3"

viewStack : ["VIEW3", "VIEW2", "VIEW1" ]

but when i again click on "open view 2"

viewStack : [ "VIEW2","VIEW3", "VIEW2", "VIEW1" ]

THAT IS THE PROBLEM

is there any way to reuse VIEW 2 from viewStack?

every view has some network task. so loading view every time is not a good idea.

thanks in advanced. for any help. 

i have searched a lot but nothing in hand.