Show prices without taxes at product list and with taxes at checkout for a specific users group.

[mgo3]

Hi! How could I modify prestashop controllers or templates to show, for a specific users group, prices without taxes at products lists (that's done with backoffice users group options) and with taxes at checkout. I have modify the themes/VMO/templates/checkout/_partials/cart-summary-totals.tpl to show {$cart.totals.total_including_tax.value} and it was working well until I arrived to payment method options. It only shows the price with taxes if PayPal is selected but without taxes if the rest of payments methods are selected. 

Thanks!