How to disable the conversion of HTML div tag with a specific class

[netteria]

Hello

I have this code inserted at initialization .append editor

<div class = "respon span6"> such a div 50% </ div> <div class = "respon span6"> 2 50% </ div> 

I wish all of the editor was concluded between the div
Unfortunately, as I select an item block - h1, ul, .. it turns me on this div

example

<div class = "respon span6"> such a div 50% </ div> replaces on <h1> such a div 50% </ h1>

And I need

<div class = "respon span6"><h1> such a div 50%  </h1></ div>

Everything will generate editor between these tags imposed from above

Div tags respon span6 I need is to build a responsive grid, and so I want to get all tags from the editor were placed between the div

How to avoid this?
Sorry for my english
thanks in advance for your help