UNION ALL AND GROUP BY

Is it possible to run in the same sql 2000 query a union all and group by statement

what I am doing is creating a view from 4 different tables which hold a siteid in them.
then i want to get a unique list of them but dont really want to do this in 2 views

create view zAllSiteid

select call_siteid as siteid from tbl_calls
union all
select  inventory_siteid as siteid from tbl_inventory
union all
select orders_siteid as siteid from tbl_Orders


then I would do a


select siteid from zAllSite
group by siteid
order by siteid

can i do this in one query?