studentEducationOrganziationAssociationStudentIdentificationCode for multiple IDs

Delaware has a requirement to receive the 'prior student ID' for students who have received multiple state IDs (erroneously) and then went through a merge process to consolidate on one of the IDs. We have published to SEOAStudentIdentificationCode these values from our SIS, and would like to provide this as a route for vendors and programs to track down issues (a student is registered from the Ed-Fi API for an assessment, then the ID they were registered under is the 'loser' in the merge process) In rare cases, this may happen multiple times to a student, so they would have multiple IDs. This can happen multiple times in the same school year.

We would like to publish all the previous IDs to Ed-Fi. The SEOAStudentIdentificationCode structure is a little strange- it has a text field in the primary key of assigningOrganizationCode, which is not related (FK) to any other table. My initial slack question is what this was intended for.

We are currently considering 3 solutions:

1. DEX (PowerSchool) published a comma-delimited list of the IDs. The field is 60 characters, but it would strange if there were over 60 characters of prior IDs. The issue with this is it doesn't make real good relational sense and also is harder for vendors to deal with.
2. Publish with different descriptors: studentIdentificationSystemDescriptors#Previous_Id1, studentIdentificationSystemDescriptors#Previous_Id2. Not great.
3. Use the assigningOrganziationCode as an Ordinal for the various previous_ids ('StateSystemMerge1', 'StateSystemMerge2')

None of these seem great, so I wanted to bounce this off Ed-Fi and also get a sense of if the structure may be changing at some time in the future that could affect the best way to do this. Could I get your thoughts and a recommendation?