Multiple primary keys

What do I need to do to handle the following record creation logic:
I have account 1, account 2 and account 3 fields. I also have Record ID field.
Record ID should be unique and I have set it up, however I need to database not to create a new record id if the combination of account 1+account2+account3 already exists in the database.
Is there any way to accomplish this?


You can create a new free text field with string formulas to combine the field values of account 1, account 2, and account 3. Then, set the unique attribute to that free text field.

Thank you!