identify if two or more elements in sequence have same property
<p>I want to identify and extract the elements if two or more elements in sequence have same property inside a list.
e.g. 
i have a List
there is a property for document called Isvalid
now i want to identify if two or more documents in sequence have IsValid == true
suppose the structure is </p>

<pre><code>IsValid = false
IsValid = true
IsValid = true
IsValid = false
IsValid = true
IsValid = false
</code></pre>

<p>My query should return only elements 2 and 3 beccause only these two are in sequence and have ISvalid = true
how do i achieve it?</p>
