The order of the undoing of transactions is reverse of the order at commit time of these transactions and cannot be changed. If for some reason you need the order to be different than the usual order, the only way to do this is to recover each transaction separately (by launching the Recover dialog for each transaction individually) in the desired order.

In each transaction to be recovered, the order of the individual statements can be changed, using the Up and Down buttons in the Recover dialog.