Unfortunately no. We are not able to change the Widget to simply display business banks only. The reason for this is that not all banks have separate logins for business and personal accounts. A good example in the UK is Barclays Bank.
It is, however, possible to remove the list of most popular banks on the Widget. If you choose to do this, your customers will simply need to type in the bank name, search for the bank and pick the correct option - instead of picking the first one they see.