Our other platforms only support a 1:1 relationship between a contact and an account.
Therefore, I need the ability to restrict the selection of a Primary Contact on an Account to be associated with Contacts with the same Account at the contact record level.
I have disabled the multiple accounts to contact option in Account Settings and cleaned up all the indirect relationships. This feature resulted in inadvertently moving contacts around in our our other applications.
However, the sales team can still designate a contact as a Primary Contact on an account the contact is not "setup" under. This causes the underlying GUID/Contact_recID to "move" to a different account ID within our tertiary databases.
What I need to happen is to not allow contact1 to be associated with account1 and also be selected as the primary contact to account2. Instead, the sales rep will need to create a new contact2 and then associate that new contact as the primary contact for account2 (as well as account2 on the contact account field).
Did you try using a trigger or flow
