Diagram Editor allow simple field lookups of partial primary keys

[hinogi]

Lets say you have something like an account with an associated bank

-- Account
ACC_NO
ACC_BANK_NO

-- Bank
BANK_NO

and in the Diagram editor I want to indicate that with only the ACC_BANK_NO you can look up the bank for that account by matching BANK_NO. Now that the primary key has two columns for Account I am always forced to map both values currently. is there a way around this?