mailing_mailing_views_menus.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
  <data>
    <record model="ir.ui.menu" id="mass_mailing.mass_mailing_menu_root">
      <field
        name="groups_id"
        eval="[(6,0,[ref('mass_mailing.group_mass_mailing_user')])]"
      />
    </record>
  </data>
</odoo>