Excel Advance what/if/else statement

How do I create a statement that will give me the desire results displayed in the example attached. Currently in my spreadsheet I have the same  number (accounttop) for the same number and same bottom_account_2. How do I get it to display on one line, where top_account goes into top_account and top_account_1, this of course will only happen when  the number in colunm A and  G is duplicated.
Bookexp.xlsx