Add a Second price in article

***** PLEASE READ CAREFULLY, OFFERS WITH DEFAULT TEXT WILL BE IGNORED***** This is a full project description. Only little questions are admitted. If user is anonymous or not have as default a specific fixed group (ID 4), I want to show as second price, the price for that fixed group. The project is made with Prestashop 1.6 default template. I need to show it in main page and product page (see attached files). I need this html: <br> <span class="second-price">***Output***</span> CSS programming is not needed. You have to send me the default theme's tpl modified files and other needed files.