public void set(ListTab selectedListTab) {
        lists = new ArrayList<>();
        List listRegObj = EntityManagerUtils.createNativeQuery(em,
                    "SELECT * FROM REGION").getResultList();
            topLists.add(getGroup("Списки Регионов", listRegObj ));
        
       List listStrObj = EntityManagerUtils.createNativeQuery(em,
                    "SELECT * FROM Street").getResultList();
            topLists.add(getGroup("Списки Улиц", listStrObj ));
}

private SelectItemGroup getGroup(String name, List list) {
        SelectItemGroup group = new SelectItemGroup(name);
        List<SelectItem> items = new ArrayList<>();
        for (Object obj : list) {
            Object[] row = (Object[]) obj;
            items.add(new SelectItem(row[0], row[1].toString()));
        }
        group.setSelectItems(items.toArray(new SelectItem[] {}));
        return group;
    }

 private SelectItemGroup getGroup(String name, List list) {
        SelectItemGroup group = new SelectItemGroup(name);
        List<SelectItemGroup> newGroups = new ArrayList<>();
        List<SelectItem> regionList = new ArrayList<>();
        for (Object obj : list) {
            Object[] row = (Object[]) obj;

            SelectItemGroup newSelectItemGroup = new SelectItemGroup(row[1].toString());
            List regions = EntityManagerUtils.createNativeQuery(em,
                    "SELECT * FROM REGION).getResultList();

            for (Object region : regions)
            {
                Object[] regionRow = (Object[]) region;
                regionList.add(new SelectItem(regionRow[0], regionRow[1].toString()));
            }

            newSelectItemGroup.setSelectItems(regionList.toArray(new SelectItem[] {}));
            newGroups.add(newSelectItemGroup);
        }
        group.setSelectItems(newGroups.toArray(new SelectItem[] {}));
        return group;
    }