You can and should be able to transfer money (i.e., deposit) into any bank account without having to be the owner of the bank account or the beneficiary. The companies may be able to only release to the beneficiaires, but you as the executor can instruct the bank to submit monies from each account (equal portion for example) into the account to pay estate's bills or you can agree with your siblings on who will pay what (put it in writing, have everyone sign a notarized affidavit) and then instruct the bank (go in to work with executive staff) to transfer from X's account into your dad's account or from A to B to C. As executor, you should have no problem giving these directions and having the companies comply.