Accessing every other data point in a dynamic data type (question in attached images)

So I thought that my question would be best explained through word equation editor, so I have attached screenshots explaining my situation and what I am trying to do (temp 2).
[img]http://forums.ni.com/ni/attachments/ni/170/1006091/1/temp1.png[/img]
[img]http://forums.ni.com/ni/attachments/ni/170/1006091/2/temp2.png[/img]