How do we override the Account Rules created for Bank Transfer related External transactions?

When we perform Create Accounting for Cash Management, the External transactions created through bank transfers get accounted to a specific account irrespective of the cash account of the selected bank account, which seems to be due to the 'Account Rules' setup configured during implementation. But we want to perform the accounting with the actual Cash account, and we're unable to do so due inability to deactivate these account rules (Status change options are blurred).

How do we overcome/deactivate these account rules and have the External transactions accounted with the actual bank's cash & offset account?