pulling months from customer bases with different start dates

[ammartino44]

Hello. I have a list of customer sets with start dates (one month) down column A. Then from B:M, I have each month in that customers life. For example, for customer set 3/1/2014, 1 = March 2= April etc. How can I do a lookup for months to grab ALL customer sets from that specific months? In the spreadsheet attached, I show the results that I want for March of 2015. Ideally I would like a formula that would reference the month and grab appropriate values. Thanks. Spreadsheet attached.

[mikeTRON]

I would use a pivot table to aggregate by month instead of a clever formula.