public function removeFromGroup($sGroupID = null)
    {
        if ($sGroupID != null && $this->inGroup($sGroupID)) {
            $oGroups = oxNew(\OxidEsales\Eshop\Core\Model\ListModel::class);
            $oGroups->init('oxobject2group');
            $sSelect = 'select * from oxobject2group where oxobject2group.oxobjectid = "' . $this->getId() . '" and oxobject2group.oxgroupsid = "' . $sGroupID . '" ';
            $oGroups->selectString($sSelect);
            foreach ($oGroups as $oRemgroup) {
                if ($oRemgroup->delete()) {
                    unset($this->_oGroups[$oRemgroup->oxobject2group__oxgroupsid->value]);
                }
            }
        }
    }