I have an Entity named "Loan". I have another entity named "Borrower". A loan can have many borrowers. And a borrower can have many loans. I have created an intersect entity to create the N:N relationship. On the intersect entity I have a field named "Type", the option can be "Primary" or "Co-borrower". A new Borrower/Loan is added to the "loan" record with a quick create form which is accessed by clicking "+ Add New Borrower" on a subgrid on the loan form. The Borrower/Loan relationship entity has a lookup field to "Borrower".
I want to stop the user from creating more than one "Primary" Borrower/Loan relationship. Is there a way to build a workflow that displays an error message to the user if they make more than one Borrower/Loan relationship "Primary"?