private function queryAddWrhsGroupPrice($query)
    {
        $asCatInv = $this->getAliasForCataloginventoryTbl($query);
        if ($asCatInv) {
            $scope = $this->scope->getCurrentScope();
            /* there is 'cataloginventory_stock_item' table - we can JOIN our tables to get warehouse group price  */
            /* don't join warehouse group prices for collection in adminhtml mode */
            if ($scope == \Magento\Framework\App\Area::AREA_FRONTEND) {
                /* LEFT JOIN prxgt_wrhs_group_price */
                $tbl = $this->resource->getTableName(EGroupPrice::ENTITY_NAME);
                $as = self::AS_WRHS_GROUP_PRICE;
                $cols = [AWrhsProd::A_PRICE_WRHS_GROUP => EGroupPrice::A_PRICE];
                $cond = "$as." . EGroupPrice::A_STOCK_ITEM_REF . "=$asCatInv." . Cfg::E_CATINV_STOCK_ITEM_A_ITEM_ID;
                $query->joinLeft([$as => $tbl], $cond, $cols);
                /* filter by current customer group */
                $groupId = $this->getCustomerGroup();
                $byGroup = "$as." . EGroupPrice::A_CUST_GROUP_REF . '=' . (int)$groupId;
                $query->where($byGroup);
            }
        }
    }