Taking a guess at what you are trying to do, you could consider something like this:

In the individual balance sheet tables add a column and enter the entity name in each cell.
Copy-paste the data in the individual balances sheets one-by-one into a "combined" table.
Set up a new "Merged" balance sheet table with entity names listed across the top row and account titles down the first column.
Enter the following formula in B2 and fill or copy to the right and down in that table:
=SUMIFS(Combined::$C,Combined::$B,$A2,Combined::$A,B$1)
If your region uses , as a decimal separator then instead enter:
=SUMIFS(Combined::$C;Combined::$B;$A2;Combined::$A;B$1)
SG