Generate nested XML tree using stored procedure in ASP.Net

Hello,

is it possible to combine different XML trees as nested into a new one? The XMLs are created using stored procedures in SQL Server. I'm giving you below the code for one of the tables. 

 SELECT
'TEST' AS [table/@t],
(
SELECT
GroupName as [@g],
(SELECT
Code [@val],
(SELECT
ColumnName as [col/@c],
CASE name
		WHEN 'A' THEN A
		WHEN 'B' THEN B
		WHEN 'C' THEN C
		WHEN 'D' THEN D
		WHEN 'E' THEN E
		WHEN 'F' THEN F
		WHEN 'G' THEN G
		WHEN 'H' THEN H
	END  AS [col/value]
FROM sys.columns 
  CROSS JOIN TEST c1
  INNER JOIN COLUMN_GROUP r1
	  ON sys.columns.name=r1.columnname
WHERE object_id = OBJECT_ID('TEST')
and r1.GroupName=r2.GroupName  and  c1.Id=c2.Id
ORDER BY column_id
FOR XML PATH(''),TYPE)
FROM TEST c2
FOR XML PATH('u'),TYPE
)
FROM sys.columns 
  CROSS JOIN TEST c3
  INNER JOIN COLUMN_GROUP r2
	  ON sys.columns.name=r2.columnname
WHERE object_id = OBJECT_ID('TEST') 
GROUP BY GroupName
FOR XML PATH('group'),TYPE
)AS [table]
FOR XML PATH('')

Here's is how I need the result to be: 

<f n=**value**>
  <table t='TEST'>
    .....
  </table>
  <table t='TEST2'>
    ....
  </table>
  <table t='TEST3'>
    .....
  </table>
     ....
</f>

Any kind of help would be appreciated.

Thank you in advance.