title: Creating subTable within subTable with PrimeFaces
body: <p>I need to know how to create table such as below in PrimeFaces. 
  I have tried with subTree within subTree but it's not allowed in PrimeFaces.</p>
  
  <p>For this I have 3 classes:
  Product: name, containing array of Items
  Item: name, containing array of content
  Content: name</p>
  
  <p>I need also to perform for loop but it seems it's allowed in panelGrid.</p>
  
  <p>Col1.............Col2..........Col3</p>
  
  <hr>
  
  <p>Product1......Item 1.......content 1</p>
  
  <p>....................................content 2</p>
  
  <p>....................................content 3</p>
  
  <p>................... Item 2.......content 5</p>
  
  <p>....................................content 6</p>
  
  <hr>
  
  <p>Product2......Item 3.......content 9</p>
  
  <p>....................................content 10</p>
  
  <p>....................Item 4.......content 15</p>
  
  <p>.....................................content 17</p>