Como agrupar una columna subselect ? alias ?

[m1di]

Hola amigos estoy tratando de agrupar un alias pero no encuentro como hacerlo.. me gustaria por favor puedan ayudarme les gradeceria.

a continuacion les muestro el codigo.

select '', '' AS MES,

(select top 1 case
WHEN RTRIM(caff.SALSTERR) between '10000' and '19999' THEN 'LA GRAN CARACAS'
WHEN RTRIM(caff.SALSTERR) between '20000' and '29999' THEN 'ZULIA-FALCON'
WHEN RTRIM(caff.SALSTERR) between '30000' and '39999' THEN 'CENTRO'
WHEN RTRIM(caff.SALSTERR) between '40000' and '49999' THEN 'LOS ANDES'
WHEN RTRIM(caff.SALSTERR) between '50000' and '59999' THEN 'LARA - LOS LLANOS'
WHEN RTRIM(caff.SALSTERR) between '60000' and '69999' THEN 'ORIENTE'
WHEN RTRIM(caff.SALSTERR) = '70000' THEN 'OFICINA'
end as ZONA FRom [SOP30200] caff where caff.SALSTERR = caf.SALSTERR group by caff.SALSTERR) as ZONA,


0 unidades_total,

cast(isnull(((select top 1 sum(quantity) FROM [SOP30300] d
inner join [SOP30200] fIn on d.SOPNUMBE = fIn.SOPNUMBE
where fIn.VOIDSTTS<>1
and fIn.SALSTERR = caf.SALSTERR
and fIn.SOPTYPE='3'
and fIn.SALSTERR between '10000' and '70000'
and fIn.DOCDATE between '01/01/2011' and '31/12/2011'
and d.[cmpntseq] not in ('16384','32768'))),0) -

isnull(((select top 1 sum(quantity) FROM [SOP30300] d
inner join [SOP30200] fIn on d.SOPNUMBE = fIn.SOPNUMBE
where fIn.VOIDSTTS<>1
and fIn.SALSTERR = caf.SALSTERR
and fIn.SOPTYPE='4'
and fIn.SALSTERR between '10000' and '70000'
and fIn.DOCDATE between '01/01/2011' and '31/12/2011'
and d.[cmpntseq] not in ('16384','32768'))),0) as int) TOTAL


from SOP30200 caf
inner join SOP30300 de on caf.SOPNUMBE = de.SOPNUMBE

where
caf.VOIDSTTS<>'1'
and de.[cmpntseq] not in ('16384','32768')
and (caf.SOPTYPE = '3' or caf.SOPTYPE = '4')
and( caf.SALSTERR between between '10000' and '79999')
and (caf.DOCDATE between '01/01/2011' and '31/12/2011')

group by caf.SALSTERR

el resultado q me da en la columna ZONA es el siguiente.
CENTRO
CENTRO
AMERICA
ZULIA
ZULIA

quisiera q apareciece
CENTRO
AMERICA
ZULIA

Gracias y espero puedan ayudarme.