Group/Ungroup columns based on Date

I have a table with data going back a few years but only want to show the last 13 months and want the rest grouped. Is there a way to do this with a macro? I was thinking to put in an autoopen macro.

One of the cells in the sheet has a formula to name it the same as the folder and the folder is named by month, so i can use that as a reference.

Any ideas?

No worries now, it's sorted.

On sheet 2 i have the current month and on a cell on sheet 1 i have the following formula

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Then i have written this code to group the columns i wish to hide

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Have you tried Pivot Tables for analysing your data.
the Pivot table has the posibility to show data for each day,week,month, year or what ever you want for a specific time period and group all data before or after this date as one group.

Maybe not what you are looking for, but I tought I'd mention it in case you had not tried Pivot Table, and this sounded like a typical Pivot table project...