Allow vote and comments only for a special group

If i am not wrong you may decide to allow vote to everyone, registered or bought.
Is it possible to use a custom group?

I sell subscriptions, with this subs the customers receive at home 2 bottles of wine every months.
We sell also the same bottles of wine.
I would like to allow all the users with a valid subscription to vote the product.
With the current options I cannot do.
Do you have any ideas or suggestions?

There is no option for that.

You would have to edit the file "form" of the view "vote" via the menu Display->Views and change the line:
if(($access_vote == 'registered' && empty($hikashop_vote_user_id)) || ($access_vote == 'buyed' && $purchased == 0)){

to something like that:
$my = hikashop_loadUser(true);
$config =& hikashop_config();
$userGroups = JAccess::getGroupsByUser($my->id, (bool)$config->get('inherit_parent_group_access'));
$allowedGroups= array('XXX','YYY');
$inter = array_intersect($userGroups,$allowedGroups);
if(!empty($inter)){

where XXX and YYY are the ids of the user groups allowed access to the voting.

Thank you Nicolas, you are the best!