How to insert extra item to template each

I have such template

<tbody>
  
    
  
</tbody>

I want to insert extra item into this rendering template list, something like this:

<tbody>
  
    
      
    
      
    
  
</tbody>

But the problem is this solution will skip some topic when someCondition is true, ie it will note insert but replace.

Is there a solution to add an item to template render list?