Yes, you can use the same bank accounts to fund multiple investment accounts.
However, please check the correct bank details of the account to which you should transfer your funds and make sure your bank account is the primary account linked to your DEGIRO profile. You can see this under Profile - Linked Bank accounts. The details of the receiver account can be found by clicking on 'Deposit/Withdraw' and then on 'Manual transfer to DEGIRO'. If your investment account does not (yet) have a linked cash account, please state the username of the target account in the payment description of your bank transfer.