Is it possible to merge multiple tables into one large table?

Hi,

I'm having an issue where I want to merge lots of tables held in different spreadsheets into one large table so that I can use it in a pivot table. The attached spreadsheet demonstrates what I mean:

So there are 3 different accounts held in the first 3 tabs. These all have the same columns and format. I want to merge these automatically into the table that is in tab 4 so that I can use the pivot table also demonstrated in this tab.

What I want to happen is when I add rows to the tables in the first 3 tabs, these are automatically populated onto the 'overall' table in the 4th tab. (I'm aware I could do this manually, but for what I'm using this for these will be dozens of tables with hundreds of rows updated monthly).

Is this possible? Basically it doesn't matter how it's done, as long as i can show the information held in the pivot table each month end.

Please let me know if you require any more information