Replace Inner SELECT UNION with your table name.
SELECT
[QGroup], SUM([values]) AS [sum-value-quarterly]
FROM
(
SELECT *, CEILING([counter] /3.0) AS [QGroup]
FROM
(
SELECT 1 AS [counter],10 AS [values]
UNION
SELECT 2 AS [counter],14 AS [values]
UNION
SELECT 3 AS [counter],16 AS [values]
UNION
SELECT 4 AS [counter],20 AS [values]
UNION
SELECT 5 AS [counter],30 AS [values]
UNION
SELECT 6 AS [counter],50 AS [values]
UNION
SELECT 7 AS [counter],25 AS [values]
UNION
SELECT 8 AS [counter],35 AS [values]
UNION
SELECT 9 AS [counter],10 AS [values]
UNION
SELECT 10 AS [counter],15 AS [values]
UNION
SELECT 11 AS [counter],25 AS [values]
)AS X
)AS Y
GROUP BY [QGroup]
ORDER BY [QGroup]