I don't know much about SSIS but it seems to me that the only way to process things in the correct order would be to "take control" of the situation. With that thought in mind, here's the basic concept for how to create a "Control" table. I can't explain how to use it in SSIS but it seems like it should be an easy thing to "step through" because it would be easy to do in a T-SQL only solution.

DROP TABLE #Control

GO

--===== Simulate a process that captures all of the

-- file names in a table with an extra column

-- for processing order.

SELECT d.PricesFileName

,ProcessOrder = CAST(0 AS INT)

INTO #Control

FROM

(

SELECT 'PRICES_AM_20160622.TXT' UNION ALL

SELECT 'PRICES_AM_20160623.TXT' UNION ALL

SELECT 'PRICES_AP_20160622.TXT' UNION ALL

SELECT 'PRICES_AP_20160623.TXT' UNION ALL

SELECT 'PRICES_EU_20160622.TXT' UNION ALL

SELECT 'PRICES_EU_20160623.TXT'

) d (PricesFileName)

;

--===== Parse the file names to establish the process order and update the control table

-- with the correct order.

WITH cteCreateProcessOrder AS

(

SELECT ProcessOrder

,RN = ROW_NUMBER() OVER (ORDER BY SUBSTRING(PricesFileName,11,8)

,CASE

WHEN SUBSTRING(PricesFileName,8,2) = 'AP' THEN 1

WHEN SUBSTRING(PricesFileName,8,2) = 'EU' THEN 2

WHEN SUBSTRING(PricesFileName,8,2) = 'AM' THEN 3

ELSE 'UNKNOWN TYPE OF FILE DETECTED'

END)

FROM #Control

)

UPDATE cteCreateProcessOrder

SET ProcessOrder = RN

;

--==== Let's see what we have in the #Control table.

SELECT * FROM #Control ORDER BY ProcessOrder

;

The content of the control table, sorted by the ProcessOrder column looks like this...

PricesFileName ProcessOrder

---------------------- ------------

PRICES_AP_20160622.TXT 1

PRICES_EU_20160622.TXT 2

PRICES_AM_20160622.TXT 3

PRICES_AP_20160623.TXT 4

PRICES_EU_20160623.TXT 5

PRICES_AM_20160623.TXT 6

(6 row(s) affected)