Thanks Klas,
I chose to use some custom javascript. I will let my solution if someone else need it:
1) Create a "start" and "end" Div field and put all group fields inside this Div.
2) Open the "start" Div field and put this code in "Custom Attributes":
id="my_div_id" style="display:none;"
3) Create a javascript field (seblod code pack) and put this code with your conditional:
jQuery(function($){
var my_condition_var = $('#my_condition_field').val();
$('#my_div_id *').attr("disabled", true); // Disables all fields inside the div to handle with eventual required fields
if (my_condition_var = 'some condition') { // This is the condition to show the Div with group of fields
$('#my_div_id').show();
$('#my_div_id *').attr("disabled", false); // enable all fields inside the div again
}
});
Of course you have to change the id and fields name to yours.